[Healeys] Healeys Digest, Vol 17, Issue 216
Craig Cooper
craiginchico at gmail.com
Thu Dec 26 18:50:49 MST 2024
Re: overflowing fuel into intake drain tube
I wonder if fuel could be entering the float bowl from beneath the seat
body where it screws into the float lid. If you don't have a good seal
there, fuel can continue to enter the float bowl as long as the fuel system
is pressurized. My SU supplier sells a small washer that goes under the
seat and, although I've seen lots of seats installed without washers, they
cleaned up wet/overly rich running in a pair of carbs I worked on
recently. If it's just the rear carburetor that has the issue, I'd be
tempted to switch float lids and see if the problem moves to the front.
On Tue, Dec 24, 2024 at 10:59 AM <healeys-request at autox.team.net> wrote:
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> Today's Topics:
>
> 1. Re: overflowing fuel into intake drain tube (Michael Salter)
> 2. Re: overflowing fuel into intake drain tube (Hank Leach)
> 3. Re: overflowing fuel into intake drain tube (Roland Wilhelmy)
> 4. carb damper (=?utf-8?Q?healeymanjim?=)
> 5. Re: overflowing fuel into intake drain tube (richard mayor)
> 6. Re: carb damper (richard mayor)
>
>
>
> ---------- Forwarded message ----------
> From: Michael Salter <michaelsalter at gmail.com>
> To: Hank Leach <gradea1 at charter.net>
> Cc: Healey team <healeys at autox.team.net>
> Bcc:
> Date: Mon, 23 Dec 2024 15:21:41 -0500
> Subject: Re: [Healeys] overflowing fuel into intake drain tube
> Sorry Hank but I think you have that wrong.
> In and SU carb,and for that matter almost every other type of carburettor,
> fuel DOES NOT pump out through the jet.
> The fuel level, as mentioned previously, is controlled by the float
> chamber float valve to never actually be above the top of the jet. It is
> only the flow of air across the carburettor "bridge", where the jet is
> positioned, that draws fuel up through the jet to be atomized into the
> airflow and into the inlet manifold.
> This is all related to Bernoulli's principle
> <https://www.google.com/search?client=firefox-b-d&q=Bernoulli%27s+principle>
> which is the basis upon which all carburettors work.
> If fuel is coming out of the jet when the engine is not running then the
> mechanism controlling the float level is not operating correctly.
>
> M
>
> On Mon, Dec 23, 2024 at 1:37 PM Hank Leach via Healeys <
> healeys at autox.team.net> wrote:
>
>> Ah! A rebel in the crowd. I looked at a bunch of photos of 1953 100
>> engines on the web. Many are configured as mine with NO FLOAT BOWL DRAIN
>> TUBES. The *later *engine setups have drain tubes in the lid. This
>> includes the cars using H6 carbs (Lemans). Also, on these early designs
>> there is a different carb adaptor. Part 1B1672 which has a lower drain in
>> the casing up to engine # 139915 (my engine 139563). Of course Moss,
>> etc. only sell the later style products. but some books show the solid
>> float lids and some show vented lids and some show a lid with a drain tube
>> (air vent).
>>
>> So, in theory the way the early system works; fuel is inlet from the
>> float chamber and enters the jet thru a hole in the tube positioned between
>> the two gland washers which are to keep the fuel intact. when the choke is
>> pulled that jet hole is lowered to send in, as the British say..."a neat
>> petrol supply" to start the car.
>> Now, if you turn on the key, fuel pumps in and is moved thru the jet into
>> the throttle area and into the manifold. Unless the engine is now turning
>> and suction from the piston is active, the fuel will run haplessly in the
>> intake manifold and out the drain tube to the ground. So the important
>> procedure in these early systems is turn the key and crank the engine
>> immediately or it will overflow fuel down the drain tube. I'm here
>> testing the operation of the carburetors in a static mode-its not going to
>> do anything but spew fuel to the ground. Right?
>>
>> The later design using a float bowl vent tube also send fuel into the
>> manifold but without a drain tube the fuel will go into the engine, as the
>> Moss PDF described, diluting the oil and washing the cylinders. Sounds like
>> the best method of starting up is to crank the engine as soon as you hear
>> the fuel pump click...I typically have waited until the pump stopped (float
>> bowls full) before cranking. Live and learn?Hank
>>
>>
>> --------------------
>>
>> From: "WILLIAM B LAWRENCE" <ynotink at msn.com>
>> To: "Hank Leach via Healeys" <healeys at autox.team.net>, "Bob Haskell" <
>> rchaskell at earthlink.net>, "richard mayor" <boyracer466 at gmail.com>, <
>> gradea1 at charter.net>
>> Sent: December 22, 2024 at 9:29 PM PST
>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>>
>> I’d like to be able to answer that, but I have to confess I’ve modified
>> the induction system on mine (I know, I’m going to Hell) and I’m a little
>> fuzzy on the details. If memory serves (a doubtful premise) the float bowls
>> originally had an open vent arrangement on the top with no drain tubes. The
>> car was built up from several dozen boxes of parts, so that may not have
>> been correct. About 20 years ago I built a pair of H6s and installed those
>> with drain tubes. The car is a bitsa anyway so originality is secondary, or
>> maybe tertiary…
>>
>> Bill Lawrence
>> BN1 554
>> ------------------------------
>> *From:* Healeys <healeys-bounces at autox.team.net> on behalf of Hank Leach
>> via Healeys <healeys at autox.team.net>
>> *Sent:* Monday, December 23, 2024 1:59 AM
>> *To:* Bob Haskell <rchaskell at earthlink.net>; richard mayor <
>> boyracer466 at gmail.com>
>> *Cc:* healeys <healeys at autox.team.net>
>> *Subject:* Re: [Healeys] overflowing fuel into intake drain tube
>>
>> Thanks Bob-yes the Moss site confirms they have alternate nitrile floats
>> and about $20 each. Looking at the diagram there is a drawing of the float
>> chamber overflow AUC1866 (451-250) $24.99 each. I do not have these
>> overflows on my float bowls (as Richard Mayor mentioned their location)
>> Instead the early cars have silver vent caps and a red washer which allows
>> air out and those two intake manifold copper drain pipes at the bottom of
>> the carb intakes. There is a PDF note on that part which reads:
>>
>> "These pipes are open to the atmosphere, for two reasons: first (and most
>> important) they allow the fuel coming into the float bowl to displace the
>> air in there so the fuel can reach its correct level in a timely manner.
>> Second, if the float valve (needle-and-seat) should stick open (as they do
>> when a bit of grit is trapped on the mating surfaces) the fuel will be
>> piped out and down – away from the engine. If the *fuel could not escape
>> through the overflow pipe, it would pour down the carburetor throat into
>> the engine*. With that much liquid gasoline, not all of it will vaporize
>> before the spark plug fires. The fuel that does vaporize will make the
>> mixture so rich (as if the choke were engaged) the car will belch black
>> smoke out the tailpipe. The engine will eventually flood and die."
>>
>> The point here is that not having those overflows on the float bowls; the
>> overflow is actually after the throttle plates on my car. I wonder how Bill
>> Lawrence's early car is configured and if he has float bowl overflows or
>> intake overflows? Is it possible that this is a clue to my delima? Trapped
>> air? Hank
>> --------------------
>>
>> From: "Bob Haskell" <rchaskell at earthlink.net>
>> To: <gradea1 at charter.net>, "richard mayor" <boyracer466 at gmail.com>
>> Cc: "healeys" <healeys at autox.team.net>
>> Sent: December 22, 2024 at 4:28 PM PST
>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>>
>> Hank,
>>
>> I think the newest floats are made from nitrile rubber - nitrophyl, not
>> plastic. Supposedly unsinkable.
>>
>> Cheers,
>>
>> Bob Haskell
>> Austin-Healey 3000 roadster registrar
>>
>> On 12/22/24 17:49, Hank Leach via Healeys wrote:
>>
>> I actually cannot figure where all the fuel is coming from. In static
>> mode-key off and float bowls at proper level-with dashpot and piston
>> removed, no fuel is apparent (as Michael says about 1/8" below jet or as
>> you say equal to float setting). However, with key on and carbs together
>> it's a different story-fuel is flowing steadily. The suggestion that was
>> made that we really need to have clear plastic float bowls has merit. I
>> cannot tell if the brass float is pushing hard enough to shut off the peg
>> on the valve. When held shut by hand its positive.
>>
>> If the float is "heavy", then it will not effect enough pressure on the
>> peg to stop the flow. This is why someone suggested plastic floats instead
>> of brass. Fuel is the shut off mechanism. I have swapped float and needle
>> valves from front to rear carb in hopes that the front one will now start
>> leaking. That may be a clue to the issue. Waiting for a dry day (next
>> year?) to test that theory.
>> --------------------
>>
>> From: "richard mayor" <boyracer466 at gmail.com> <boyracer466 at gmail.com>
>> To: "Leach Hank" <gradea1 at charter.net> <gradea1 at charter.net>
>> Cc: "healeys" <healeys at autox.team.net> <healeys at autox.team.net>
>> Sent: December 22, 2024 at 2:23 PM PST
>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>> Hank,
>>
>> If I read your post correctly, the fuel is coming out of the jet in the
>> carburetor into the intake manifold and then out the drain tube. Not from
>> the overflow tube on the float chamber. I’ll proceed with this assumption.
>>
>> The level of fuel at the jet is the same level as that in the float
>> chamber. That is the way these SU carbs are designed. That is why float
>> level is so important. If fuel is flowing out of the jet before the
>> needle valve shuts off the fuel supply at the float chamber then your float
>> level is set too high. You need to close the float needle valve with the
>> float at a lower level. Instead of using 7/16th as a guide, try 1/2” and
>> see if that stops the flow. But then you said you tried different
>> settings.
>>
>> Is there an obstruction that is preventing the float from rising all the
>> way to the top to close the needle valve? Try a different float. Polish
>> the post. Is there any wear in the fork or pivot in the casting that is
>> not allowing the needle to move feely into it’s seat. I think that’s where
>> the problem is.
>>
>> Richard Mayor
>> boyracer466 at gmail.com
>>
>>
>> On Dec 22, 2024, at 12:28 PM, Hank Leach via Healeys
>> <healeys at autox.team.net> <healeys at autox.team.net> wrote:
>> I have chased the cause of too much fuel exiting from the rear
>> carburetor overflow of my 100 for years. These are H4 carbs-very simple
>> design, but must be done correctly to perform. So I find that the jet is
>> out of center and piston is sticking up above the flat about 1/8"-that
>> would allow fuel to run into throttle area and out overflow drain tube.
>>
>> No way to center jet on car. Remove carburetor-a 4 hour job- and clean
>> and replace gaskets and gland washers-yes cork- and reassemble and center
>> jet...now works perfect. Re mount carburetor and connect fuel lines-another
>> 4 hour job. Both carb pistons drop with a clunk at the same time. Turn on
>> key- fuel pump clicking-overflow again leaking.
>>
>> I have reset the floats and float needles (brass) were replaced many
>> times-that's not the issue. No fuel in float bodies-they are not leaking.
>> I just cant believe its too much fuel pressure but then again, this is a
>> British Car.
>> Float is brass but when shaked it is dry. I filled the float lid with
>> carb cleaner while holding needle valve closed and no leaking. That's two
>> places checked (these are unfortunately "new" parts) Now the next leak
>> could be between the needle and jet if not closed off-also new parts-jet
>> .090. Needles are QW as specified but i also have a set of ATs which are
>> lean that I am tempted to try. Actually both needles are about the same at
>> top .089, but ATs are a bit fatter at mid range. Problem is all testing
>> stinks up the garage and creates an explosive atmosphere so best done
>> outside in the rain.
>>
>> I know some folks like Grosse Jets-but I don't-- I prefer the simple
>> brass ones with viton tips which do work if pressure is applied by forked
>> leg-also new, and set to 7/16" or MORE. With covers off, both bowls are
>> equally about 1/2 filled. Fuel pressure is a thought as it can push by the
>> stops but its the correct pump and when key on clicks fast then slows to a
>> stop... but then tick, tick which it should not do! Fuel is going out and
>> down the drain tube to my swimming pool drip pan. Im tempted to measure the
>> top of the needles to see if they are really at .089. Can't measure the new
>> jet but its stamped "9" Maybe stick in a number drill to see if its round?
>> Mind you, these carbs have about 125 miles total on them. As far as I know
>> these are "genuine SU" parts-not Moss India knockoffs.
>>
>> I really thought that the centering was the issue and took the carb off
>> for that reason which cured the drop-each drops equally with thud. That's
>> not the problem. Any suggestions? Someone says use plastic floats...Hank
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>
>
> ---------- Forwarded message ----------
> From: Hank Leach <gradea1 at charter.net>
> To: Michael Salter <michaelsalter at gmail.com>
> Cc: Healey team <healeys at autox.team.net>
> Bcc:
> Date: Mon, 23 Dec 2024 21:11:29 +0000
> Subject: Re: [Healeys] overflowing fuel into intake drain tube
> Michael-that is why I asked the question in the beginning, Where is the
> fuel coming from and what is the cure for the problem? I agree that the
> fuel is "atomized" in the throttle area and that would be the best
> condition to send it to the engine but this car is dumping fuel and I
> cannot find the mechanism to stop that flow. Suggested lighter nitrile
> floats are at the top of the list, if in fact my brass ones are bum. Bill
> Lawrence modified his intakes possibly due to fuel issues? The system on
> this early car (same as yours) is a bit "cruder" than the revised float
> bowl vent system (with no manifold drain?). And, I cannot see anything
> wrong the float setting as presently set.
> The fuel is not coming out the jet with the key off and the float bowls
> full to proper level-it is as you said below the top of the jet. Float
> valves are closed. Its when the key is on and fuel pressure is applied
> that I am getting the overflow condition. I was hoping that someone else on
> the team has had a similar experience. Hank
> --------------------
>
> From: "Michael Salter" <michaelsalter at gmail.com>
> To: "Hank Leach" <gradea1 at charter.net>
> Cc: "Healey team" <healeys at autox.team.net>
> Sent: December 23, 2024 at 12:21 PM PST
> Subject: Re: [Healeys] overflowing fuel into intake drain tube
> Sorry Hank but I think you have that wrong.
> In and SU carb,and for that matter almost every other type of carburettor,
> fuel DOES NOT pump out through the jet.
> The fuel level, as mentioned previously, is controlled by the float
> chamber float valve to never actually be above the top of the jet. It is
> only the flow of air across the carburettor "bridge", where the jet is
> positioned, that draws fuel up through the jet to be atomized into the
> airflow and into the inlet manifold.
> This is all related to Bernoulli's principle
> <https://www.google.com/search?client=firefox-b-d&q=Bernoulli%27s+principle>
> which is the basis upon which all carburettors work.
> If fuel is coming out of the jet when the engine is not running then the
> mechanism controlling the float level is not operating correctly.
>
> M
>
> On Mon, Dec 23, 2024 at 1:37 PM Hank Leach via Healeys <
> healeys at autox.team.net> wrote:
>
>> Ah! A rebel in the crowd. I looked at a bunch of photos of 1953 100
>> engines on the web. Many are configured as mine with NO FLOAT BOWL DRAIN
>> TUBES. The *later *engine setups have drain tubes in the lid. This
>> includes the cars using H6 carbs (Lemans). Also, on these early designs
>> there is a different carb adaptor. Part 1B1672 which has a lower drain in
>> the casing up to engine # 139915 (my engine 139563). Of course Moss,
>> etc. only sell the later style products. but some books show the solid
>> float lids and some show vented lids and some show a lid with a drain tube
>> (air vent).
>>
>> So, in theory the way the early system works; fuel is inlet from the
>> float chamber and enters the jet thru a hole in the tube positioned between
>> the two gland washers which are to keep the fuel intact. when the choke is
>> pulled that jet hole is lowered to send in, as the British say..."a neat
>> petrol supply" to start the car.
>> Now, if you turn on the key, fuel pumps in and is moved thru the jet into
>> the throttle area and into the manifold. Unless the engine is now turning
>> and suction from the piston is active, the fuel will run haplessly in the
>> intake manifold and out the drain tube to the ground. So the important
>> procedure in these early systems is turn the key and crank the engine
>> immediately or it will overflow fuel down the drain tube. I'm here
>> testing the operation of the carburetors in a static mode-its not going to
>> do anything but spew fuel to the ground. Right?
>>
>> The later design using a float bowl vent tube also send fuel into the
>> manifold but without a drain tube the fuel will go into the engine, as the
>> Moss PDF described, diluting the oil and washing the cylinders. Sounds like
>> the best method of starting up is to crank the engine as soon as you hear
>> the fuel pump click...I typically have waited until the pump stopped (float
>> bowls full) before cranking. Live and learn?Hank
>>
>>
>> --------------------
>>
>> From: "WILLIAM B LAWRENCE" <ynotink at msn.com>
>> To: "Hank Leach via Healeys" <healeys at autox.team.net>, "Bob Haskell" <
>> rchaskell at earthlink.net>, "richard mayor" <boyracer466 at gmail.com>, <
>> gradea1 at charter.net>
>> Sent: December 22, 2024 at 9:29 PM PST
>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>>
>> I’d like to be able to answer that, but I have to confess I’ve modified
>> the induction system on mine (I know, I’m going to Hell) and I’m a little
>> fuzzy on the details. If memory serves (a doubtful premise) the float bowls
>> originally had an open vent arrangement on the top with no drain tubes. The
>> car was built up from several dozen boxes of parts, so that may not have
>> been correct. About 20 years ago I built a pair of H6s and installed those
>> with drain tubes. The car is a bitsa anyway so originality is secondary, or
>> maybe tertiary…
>>
>> Bill Lawrence
>> BN1 554
>> ------------------------------
>> *From:* Healeys <healeys-bounces at autox.team.net> on behalf of Hank Leach
>> via Healeys <healeys at autox.team.net>
>> *Sent:* Monday, December 23, 2024 1:59 AM
>> *To:* Bob Haskell <rchaskell at earthlink.net>; richard mayor <
>> boyracer466 at gmail.com>
>> *Cc:* healeys <healeys at autox.team.net>
>> *Subject:* Re: [Healeys] overflowing fuel into intake drain tube
>>
>> Thanks Bob-yes the Moss site confirms they have alternate nitrile floats
>> and about $20 each. Looking at the diagram there is a drawing of the float
>> chamber overflow AUC1866 (451-250) $24.99 each. I do not have these
>> overflows on my float bowls (as Richard Mayor mentioned their location)
>> Instead the early cars have silver vent caps and a red washer which allows
>> air out and those two intake manifold copper drain pipes at the bottom of
>> the carb intakes. There is a PDF note on that part which reads:
>>
>> "These pipes are open to the atmosphere, for two reasons: first (and most
>> important) they allow the fuel coming into the float bowl to displace the
>> air in there so the fuel can reach its correct level in a timely manner.
>> Second, if the float valve (needle-and-seat) should stick open (as they do
>> when a bit of grit is trapped on the mating surfaces) the fuel will be
>> piped out and down – away from the engine. If the *fuel could not escape
>> through the overflow pipe, it would pour down the carburetor throat into
>> the engine*. With that much liquid gasoline, not all of it will vaporize
>> before the spark plug fires. The fuel that does vaporize will make the
>> mixture so rich (as if the choke were engaged) the car will belch black
>> smoke out the tailpipe. The engine will eventually flood and die."
>>
>> The point here is that not having those overflows on the float bowls; the
>> overflow is actually after the throttle plates on my car. I wonder how Bill
>> Lawrence's early car is configured and if he has float bowl overflows or
>> intake overflows? Is it possible that this is a clue to my delima? Trapped
>> air? Hank
>> --------------------
>>
>> From: "Bob Haskell" <rchaskell at earthlink.net>
>> To: <gradea1 at charter.net>, "richard mayor" <boyracer466 at gmail.com>
>> Cc: "healeys" <healeys at autox.team.net>
>> Sent: December 22, 2024 at 4:28 PM PST
>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>>
>> Hank,
>>
>> I think the newest floats are made from nitrile rubber - nitrophyl, not
>> plastic. Supposedly unsinkable.
>>
>> Cheers,
>>
>> Bob Haskell
>> Austin-Healey 3000 roadster registrar
>>
>> On 12/22/24 17:49, Hank Leach via Healeys wrote:
>>
>> I actually cannot figure where all the fuel is coming from. In static
>> mode-key off and float bowls at proper level-with dashpot and piston
>> removed, no fuel is apparent (as Michael says about 1/8" below jet or as
>> you say equal to float setting). However, with key on and carbs together
>> it's a different story-fuel is flowing steadily. The suggestion that was
>> made that we really need to have clear plastic float bowls has merit. I
>> cannot tell if the brass float is pushing hard enough to shut off the peg
>> on the valve. When held shut by hand its positive.
>>
>> If the float is "heavy", then it will not effect enough pressure on the
>> peg to stop the flow. This is why someone suggested plastic floats instead
>> of brass. Fuel is the shut off mechanism. I have swapped float and needle
>> valves from front to rear carb in hopes that the front one will now start
>> leaking. That may be a clue to the issue. Waiting for a dry day (next
>> year?) to test that theory.
>> --------------------
>>
>> From: "richard mayor" <boyracer466 at gmail.com> <boyracer466 at gmail.com>
>> To: "Leach Hank" <gradea1 at charter.net> <gradea1 at charter.net>
>> Cc: "healeys" <healeys at autox.team.net> <healeys at autox.team.net>
>> Sent: December 22, 2024 at 2:23 PM PST
>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>> Hank,
>>
>> If I read your post correctly, the fuel is coming out of the jet in the
>> carburetor into the intake manifold and then out the drain tube. Not from
>> the overflow tube on the float chamber. I’ll proceed with this assumption.
>>
>> The level of fuel at the jet is the same level as that in the float
>> chamber. That is the way these SU carbs are designed. That is why float
>> level is so important. If fuel is flowing out of the jet before the
>> needle valve shuts off the fuel supply at the float chamber then your float
>> level is set too high. You need to close the float needle valve with the
>> float at a lower level. Instead of using 7/16th as a guide, try 1/2” and
>> see if that stops the flow. But then you said you tried different
>> settings.
>>
>> Is there an obstruction that is preventing the float from rising all the
>> way to the top to close the needle valve? Try a different float. Polish
>> the post. Is there any wear in the fork or pivot in the casting that is
>> not allowing the needle to move feely into it’s seat. I think that’s where
>> the problem is.
>>
>> Richard Mayor
>> boyracer466 at gmail.com
>>
>>
>> On Dec 22, 2024, at 12:28 PM, Hank Leach via Healeys
>> <healeys at autox.team.net> <healeys at autox.team.net> wrote:
>> I have chased the cause of too much fuel exiting from the rear
>> carburetor overflow of my 100 for years. These are H4 carbs-very simple
>> design, but must be done correctly to perform. So I find that the jet is
>> out of center and piston is sticking up above the flat about 1/8"-that
>> would allow fuel to run into throttle area and out overflow drain tube.
>>
>> No way to center jet on car. Remove carburetor-a 4 hour job- and clean
>> and replace gaskets and gland washers-yes cork- and reassemble and center
>> jet...now works perfect. Re mount carburetor and connect fuel lines-another
>> 4 hour job. Both carb pistons drop with a clunk at the same time. Turn on
>> key- fuel pump clicking-overflow again leaking.
>>
>> I have reset the floats and float needles (brass) were replaced many
>> times-that's not the issue. No fuel in float bodies-they are not leaking.
>> I just cant believe its too much fuel pressure but then again, this is a
>> British Car.
>> Float is brass but when shaked it is dry. I filled the float lid with
>> carb cleaner while holding needle valve closed and no leaking. That's two
>> places checked (these are unfortunately "new" parts) Now the next leak
>> could be between the needle and jet if not closed off-also new parts-jet
>> .090. Needles are QW as specified but i also have a set of ATs which are
>> lean that I am tempted to try. Actually both needles are about the same at
>> top .089, but ATs are a bit fatter at mid range. Problem is all testing
>> stinks up the garage and creates an explosive atmosphere so best done
>> outside in the rain.
>>
>> I know some folks like Grosse Jets-but I don't-- I prefer the simple
>> brass ones with viton tips which do work if pressure is applied by forked
>> leg-also new, and set to 7/16" or MORE. With covers off, both bowls are
>> equally about 1/2 filled. Fuel pressure is a thought as it can push by the
>> stops but its the correct pump and when key on clicks fast then slows to a
>> stop... but then tick, tick which it should not do! Fuel is going out and
>> down the drain tube to my swimming pool drip pan. Im tempted to measure the
>> top of the needles to see if they are really at .089. Can't measure the new
>> jet but its stamped "9" Maybe stick in a number drill to see if its round?
>> Mind you, these carbs have about 125 miles total on them. As far as I know
>> these are "genuine SU" parts-not Moss India knockoffs.
>>
>> I really thought that the centering was the issue and took the carb off
>> for that reason which cured the drop-each drops equally with thud. That's
>> not the problem. Any suggestions? Someone says use plastic floats...Hank
>> _______________________________________________
>> Support Team.Net http://www.team.net/donate.html
>> Suggested annual donation $12.75
>>
>> Archive: http://www.team.net/pipermail/healeys
>> http://autox.team.net/archive/healeys
>>
>> Healeys at autox.team.net
>> http://autox.team.net/mailman/listinfo/healeys
>>
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>> http://autox.team.net/mailman/options/healeys/boyracer466@gmail.com
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>> Support Team.Net http://www.team.net/donate.html
>> Suggested annual donation $12.75
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>> Archive: http://www.team.net/pipermail/healeys http://autox.team.net/archive/healeys
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>
>
> ---------- Forwarded message ----------
> From: Roland Wilhelmy <sentenac.rw at gmail.com>
> To: gradea1 at charter.net
> Cc: Michael Salter <michaelsalter at gmail.com>, Healey team <
> healeys at autox.team.net>
> Bcc:
> Date: Mon, 23 Dec 2024 16:58:08 -0800
> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>
> My BN1 #724, engine number 139756, has no float bowl drain tubes, just the
> red notched washer and chrome vent at the top screw . I have never had the
> problems that you report. The floats are original. I cleaned and rebuilt
> with a Moss kit. If one of my carbs worked right and one did not, after
> replacing all rebuild able parts, I would replace the malfunctioning carb.
> If that fixes things you can explore the faulty carb at leisure. If it
> doesn't, then the rear carb wasn't the problem.
> -Roland
>
> On Mon, Dec 23, 2024, 1:19 PM Hank Leach via Healeys <
> healeys at autox.team.net> wrote:
>
>> Michael-that is why I asked the question in the beginning, Where is the
>> fuel coming from and what is the cure for the problem? I agree that the
>> fuel is "atomized" in the throttle area and that would be the best
>> condition to send it to the engine but this car is dumping fuel and I
>> cannot find the mechanism to stop that flow. Suggested lighter nitrile
>> floats are at the top of the list, if in fact my brass ones are bum. Bill
>> Lawrence modified his intakes possibly due to fuel issues? The system on
>> this early car (same as yours) is a bit "cruder" than the revised float
>> bowl vent system (with no manifold drain?). And, I cannot see anything
>> wrong the float setting as presently set.
>> The fuel is not coming out the jet with the key off and the float bowls
>> full to proper level-it is as you said below the top of the jet. Float
>> valves are closed. Its when the key is on and fuel pressure is applied
>> that I am getting the overflow condition. I was hoping that someone else on
>> the team has had a similar experience. Hank
>> --------------------
>>
>> From: "Michael Salter" <michaelsalter at gmail.com>
>> To: "Hank Leach" <gradea1 at charter.net>
>> Cc: "Healey team" <healeys at autox.team.net>
>> Sent: December 23, 2024 at 12:21 PM PST
>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>> Sorry Hank but I think you have that wrong.
>> In and SU carb,and for that matter almost every other type of
>> carburettor, fuel DOES NOT pump out through the jet.
>> The fuel level, as mentioned previously, is controlled by the float
>> chamber float valve to never actually be above the top of the jet. It is
>> only the flow of air across the carburettor "bridge", where the jet is
>> positioned, that draws fuel up through the jet to be atomized into the
>> airflow and into the inlet manifold.
>> This is all related to Bernoulli's principle
>> <https://www.google.com/search?client=firefox-b-d&q=Bernoulli%27s+principle>
>> which is the basis upon which all carburettors work.
>> If fuel is coming out of the jet when the engine is not running then the
>> mechanism controlling the float level is not operating correctly.
>>
>> M
>>
>> On Mon, Dec 23, 2024 at 1:37 PM Hank Leach via Healeys <
>> healeys at autox.team.net> wrote:
>>
>>> Ah! A rebel in the crowd. I looked at a bunch of photos of 1953 100
>>> engines on the web. Many are configured as mine with NO FLOAT BOWL DRAIN
>>> TUBES. The *later *engine setups have drain tubes in the lid. This
>>> includes the cars using H6 carbs (Lemans). Also, on these early designs
>>> there is a different carb adaptor. Part 1B1672 which has a lower drain in
>>> the casing up to engine # 139915 (my engine 139563). Of course Moss,
>>> etc. only sell the later style products. but some books show the solid
>>> float lids and some show vented lids and some show a lid with a drain tube
>>> (air vent).
>>>
>>> So, in theory the way the early system works; fuel is inlet from the
>>> float chamber and enters the jet thru a hole in the tube positioned between
>>> the two gland washers which are to keep the fuel intact. when the choke is
>>> pulled that jet hole is lowered to send in, as the British say..."a neat
>>> petrol supply" to start the car.
>>> Now, if you turn on the key, fuel pumps in and is moved thru the jet
>>> into the throttle area and into the manifold. Unless the engine is now
>>> turning and suction from the piston is active, the fuel will run
>>> haplessly in the intake manifold and out the drain tube to the ground. So
>>> the important procedure in these early systems is turn the key and crank
>>> the engine immediately or it will overflow fuel down the drain tube.
>>> I'm here testing the operation of the carburetors in a static mode-its not
>>> going to do anything but spew fuel to the ground. Right?
>>>
>>> The later design using a float bowl vent tube also send fuel into the
>>> manifold but without a drain tube the fuel will go into the engine, as the
>>> Moss PDF described, diluting the oil and washing the cylinders. Sounds like
>>> the best method of starting up is to crank the engine as soon as you hear
>>> the fuel pump click...I typically have waited until the pump stopped (float
>>> bowls full) before cranking. Live and learn?Hank
>>>
>>>
>>> --------------------
>>>
>>> From: "WILLIAM B LAWRENCE" <ynotink at msn.com>
>>> To: "Hank Leach via Healeys" <healeys at autox.team.net>, "Bob Haskell" <
>>> rchaskell at earthlink.net>, "richard mayor" <boyracer466 at gmail.com>, <
>>> gradea1 at charter.net>
>>> Sent: December 22, 2024 at 9:29 PM PST
>>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>>>
>>> I’d like to be able to answer that, but I have to confess I’ve modified
>>> the induction system on mine (I know, I’m going to Hell) and I’m a little
>>> fuzzy on the details. If memory serves (a doubtful premise) the float bowls
>>> originally had an open vent arrangement on the top with no drain tubes. The
>>> car was built up from several dozen boxes of parts, so that may not have
>>> been correct. About 20 years ago I built a pair of H6s and installed those
>>> with drain tubes. The car is a bitsa anyway so originality is secondary, or
>>> maybe tertiary…
>>>
>>> Bill Lawrence
>>> BN1 554
>>> ------------------------------
>>> *From:* Healeys <healeys-bounces at autox.team.net> on behalf of Hank
>>> Leach via Healeys <healeys at autox.team.net>
>>> *Sent:* Monday, December 23, 2024 1:59 AM
>>> *To:* Bob Haskell <rchaskell at earthlink.net>; richard mayor <
>>> boyracer466 at gmail.com>
>>> *Cc:* healeys <healeys at autox.team.net>
>>> *Subject:* Re: [Healeys] overflowing fuel into intake drain tube
>>>
>>> Thanks Bob-yes the Moss site confirms they have alternate nitrile floats
>>> and about $20 each. Looking at the diagram there is a drawing of the float
>>> chamber overflow AUC1866 (451-250) $24.99 each. I do not have these
>>> overflows on my float bowls (as Richard Mayor mentioned their location)
>>> Instead the early cars have silver vent caps and a red washer which allows
>>> air out and those two intake manifold copper drain pipes at the bottom of
>>> the carb intakes. There is a PDF note on that part which reads:
>>>
>>> "These pipes are open to the atmosphere, for two reasons: first (and
>>> most important) they allow the fuel coming into the float bowl to displace
>>> the air in there so the fuel can reach its correct level in a timely
>>> manner. Second, if the float valve (needle-and-seat) should stick open (as
>>> they do when a bit of grit is trapped on the mating surfaces) the fuel will
>>> be piped out and down – away from the engine. If the *fuel could not
>>> escape through the overflow pipe, it would pour down the carburetor throat
>>> into the engine*. With that much liquid gasoline, not all of it will
>>> vaporize before the spark plug fires. The fuel that does vaporize will make
>>> the mixture so rich (as if the choke were engaged) the car will belch black
>>> smoke out the tailpipe. The engine will eventually flood and die."
>>>
>>> The point here is that not having those overflows on the float bowls;
>>> the overflow is actually after the throttle plates on my car. I wonder how
>>> Bill Lawrence's early car is configured and if he has float bowl overflows
>>> or intake overflows? Is it possible that this is a clue to my delima?
>>> Trapped air? Hank
>>> --------------------
>>>
>>> From: "Bob Haskell" <rchaskell at earthlink.net>
>>> To: <gradea1 at charter.net>, "richard mayor" <boyracer466 at gmail.com>
>>> Cc: "healeys" <healeys at autox.team.net>
>>> Sent: December 22, 2024 at 4:28 PM PST
>>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>>>
>>> Hank,
>>>
>>> I think the newest floats are made from nitrile rubber - nitrophyl, not
>>> plastic. Supposedly unsinkable.
>>>
>>> Cheers,
>>>
>>> Bob Haskell
>>> Austin-Healey 3000 roadster registrar
>>>
>>> On 12/22/24 17:49, Hank Leach via Healeys wrote:
>>>
>>> I actually cannot figure where all the fuel is coming from. In static
>>> mode-key off and float bowls at proper level-with dashpot and piston
>>> removed, no fuel is apparent (as Michael says about 1/8" below jet or as
>>> you say equal to float setting). However, with key on and carbs together
>>> it's a different story-fuel is flowing steadily. The suggestion that was
>>> made that we really need to have clear plastic float bowls has merit. I
>>> cannot tell if the brass float is pushing hard enough to shut off the peg
>>> on the valve. When held shut by hand its positive.
>>>
>>> If the float is "heavy", then it will not effect enough pressure on the
>>> peg to stop the flow. This is why someone suggested plastic floats instead
>>> of brass. Fuel is the shut off mechanism. I have swapped float and needle
>>> valves from front to rear carb in hopes that the front one will now start
>>> leaking. That may be a clue to the issue. Waiting for a dry day (next
>>> year?) to test that theory.
>>> --------------------
>>>
>>> From: "richard mayor" <boyracer466 at gmail.com> <boyracer466 at gmail.com>
>>> To: "Leach Hank" <gradea1 at charter.net> <gradea1 at charter.net>
>>> Cc: "healeys" <healeys at autox.team.net> <healeys at autox.team.net>
>>> Sent: December 22, 2024 at 2:23 PM PST
>>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>>> Hank,
>>>
>>> If I read your post correctly, the fuel is coming out of the jet in the
>>> carburetor into the intake manifold and then out the drain tube. Not from
>>> the overflow tube on the float chamber. I’ll proceed with this assumption.
>>>
>>> The level of fuel at the jet is the same level as that in the float
>>> chamber. That is the way these SU carbs are designed. That is why float
>>> level is so important. If fuel is flowing out of the jet before the
>>> needle valve shuts off the fuel supply at the float chamber then your float
>>> level is set too high. You need to close the float needle valve with the
>>> float at a lower level. Instead of using 7/16th as a guide, try 1/2” and
>>> see if that stops the flow. But then you said you tried different
>>> settings.
>>>
>>> Is there an obstruction that is preventing the float from rising all the
>>> way to the top to close the needle valve? Try a different float. Polish
>>> the post. Is there any wear in the fork or pivot in the casting that is
>>> not allowing the needle to move feely into it’s seat. I think that’s where
>>> the problem is.
>>>
>>> Richard Mayor
>>> boyracer466 at gmail.com
>>>
>>>
>>> On Dec 22, 2024, at 12:28 PM, Hank Leach via Healeys
>>> <healeys at autox.team.net> <healeys at autox.team.net> wrote:
>>> I have chased the cause of too much fuel exiting from the rear
>>> carburetor overflow of my 100 for years. These are H4 carbs-very simple
>>> design, but must be done correctly to perform. So I find that the jet is
>>> out of center and piston is sticking up above the flat about 1/8"-that
>>> would allow fuel to run into throttle area and out overflow drain tube.
>>>
>>> No way to center jet on car. Remove carburetor-a 4 hour job- and clean
>>> and replace gaskets and gland washers-yes cork- and reassemble and center
>>> jet...now works perfect. Re mount carburetor and connect fuel lines-another
>>> 4 hour job. Both carb pistons drop with a clunk at the same time. Turn on
>>> key- fuel pump clicking-overflow again leaking.
>>>
>>> I have reset the floats and float needles (brass) were replaced many
>>> times-that's not the issue. No fuel in float bodies-they are not leaking.
>>> I just cant believe its too much fuel pressure but then again, this is a
>>> British Car.
>>> Float is brass but when shaked it is dry. I filled the float lid with
>>> carb cleaner while holding needle valve closed and no leaking. That's two
>>> places checked (these are unfortunately "new" parts) Now the next leak
>>> could be between the needle and jet if not closed off-also new parts-jet
>>> .090. Needles are QW as specified but i also have a set of ATs which are
>>> lean that I am tempted to try. Actually both needles are about the same at
>>> top .089, but ATs are a bit fatter at mid range. Problem is all testing
>>> stinks up the garage and creates an explosive atmosphere so best done
>>> outside in the rain.
>>>
>>> I know some folks like Grosse Jets-but I don't-- I prefer the simple
>>> brass ones with viton tips which do work if pressure is applied by forked
>>> leg-also new, and set to 7/16" or MORE. With covers off, both bowls are
>>> equally about 1/2 filled. Fuel pressure is a thought as it can push by the
>>> stops but its the correct pump and when key on clicks fast then slows to a
>>> stop... but then tick, tick which it should not do! Fuel is going out and
>>> down the drain tube to my swimming pool drip pan. Im tempted to measure the
>>> top of the needles to see if they are really at .089. Can't measure the new
>>> jet but its stamped "9" Maybe stick in a number drill to see if its round?
>>> Mind you, these carbs have about 125 miles total on them. As far as I know
>>> these are "genuine SU" parts-not Moss India knockoffs.
>>>
>>> I really thought that the centering was the issue and took the carb off
>>> for that reason which cured the drop-each drops equally with thud. That's
>>> not the problem. Any suggestions? Someone says use plastic floats...Hank
>>> _______________________________________________
>>> Support Team.Net http://www.team.net/donate.html
>>> Suggested annual donation $12.75
>>>
>>> Archive: http://www.team.net/pipermail/healeys
>>> http://autox.team.net/archive/healeys
>>>
>>> Healeys at autox.team.net
>>> http://autox.team.net/mailman/listinfo/healeys
>>>
>>> Unsubscribe/Manage:
>>> http://autox.team.net/mailman/options/healeys/boyracer466@gmail.com
>>>
>>>
>>> _______________________________________________
>>> Support Team.Net http://www.team.net/donate.html
>>> Suggested annual donation $12.75
>>>
>>> Archive: http://www.team.net/pipermail/healeys http://autox.team.net/archive/healeys
>>> Healeys at autox.team.nethttp://autox.team.net/mailman/listinfo/healeys
>>>
>>> Unsubscribe/Manage: http://autox.team.net/mailman/options/healeys/rchaskell@earthlink.net
>>>
>>> _______________________________________________
>>> Support Team.Net http://www.team.net/donate.html
>>> Suggested annual donation $12.75
>>>
>>> Archive: http://www.team.net/pipermail/healeys
>>> http://autox.team.net/archive/healeys
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>>> Healeys at autox.team.net
>>> http://autox.team.net/mailman/listinfo/healeys
>>>
>>> Unsubscribe/Manage:
>>> http://autox.team.net/mailman/options/healeys/michaelsalter@gmail.com
>>>
>>> _______________________________________________
>> Support Team.Net http://www.team.net/donate.html
>> Suggested annual donation $12.75
>>
>> Archive: http://www.team.net/pipermail/healeys
>> http://autox.team.net/archive/healeys
>>
>> Healeys at autox.team.net
>> http://autox.team.net/mailman/listinfo/healeys
>>
>> Unsubscribe/Manage:
>> http://autox.team.net/mailman/options/healeys/sentenac.rw@gmail.com
>>
>>
>
>
> ---------- Forwarded message ----------
> From: healeymanjim <healeymanjim at hansencc.net>
> To: "healeys at autox.team.net" <healeys at autox.team.net>
> Cc:
> Bcc:
> Date: Tue, 24 Dec 2024 09:02:20 -0800
> Subject: [Healeys] carb damper
> ran into something have not seen before. cleaning the carbs on an MGTC
> and discovered there is no damper. there is a plastic cap and a 3/16 hole
> approx 1/4 inch deep in top of piston rod. Moss shows a damper and so does
> the workshop manual. any ideas what i have here?
>
>
>
>
> ---------- Forwarded message ----------
> From: richard mayor <boyracer466 at gmail.com>
> To: Roland Wilhelmy <sentenac.rw at gmail.com>
> Cc: Leach Hank <gradea1 at charter.net>, healeys <healeys at autox.team.net>
> Bcc:
> Date: Tue, 24 Dec 2024 09:45:44 -0800
> Subject: Re: [Healeys] overflowing fuel into intake drain tube
> Hank, Here is the Moss Motors description of the need for the over-flow
> drain pipes (in the 100M reference):
>
> These pipes are open to the atmosphere, for two reasons: first (and most
> important) they allow the fuel
> coming into the float bowl to displace the air in there so the fuel can
> reach its correct level in a timely
> manner. Second, if the float valve (needle-and-seat) should stick open (as
> they do when a bit of grit i
> trapped on the mating surfaces) the fuel will be piped out and down – away
> from the engine. If the fuel
> could not escape through the overflow pipe, it would pour down the
> carburetor throat into the engine. With
> that much liquid gasoline, not all of it will vaporize before the spark
> plug fires. The fuel that does vaporize
> will make the mixture so rich (as if the choke were engaged) the car will
> belch black smoke out the
> tailpipe. The engine will eventually flood and die. The liquid fuel that
> reaches the cylinders will flush the oil
> off the cylinder walls and wind up in the crankcase. If it happens
> frequently, the loss of the oil film on the
> cylinder walls can cause premature wear. With gas in the sump, the oil is
> being diluted and the oil needs
> to be drained and replaced as soon as practical. We have heard that under
> the right conditions, gasoline
> vapors can be ignited in the crankcase with spectacular results, but we
> are still waiting for pictures.
>
> Richard Mayor
> boyracer466 at gmail.com
>
>
>
> On Dec 23, 2024, at 4:58 PM, Roland Wilhelmy <sentenac.rw at gmail.com>
> wrote:
>
> My BN1 #724, engine number 139756, has no float bowl drain tubes, just the
> red notched washer and chrome vent at the top screw . I have never had the
> problems that you report. The floats are original. I cleaned and rebuilt
> with a Moss kit. If one of my carbs worked right and one did not, after
> replacing all rebuild able parts, I would replace the malfunctioning carb.
> If that fixes things you can explore the faulty carb at leisure. If it
> doesn't, then the rear carb wasn't the problem.
> -Roland
>
> On Mon, Dec 23, 2024, 1:19 PM Hank Leach via Healeys <
> healeys at autox.team.net> wrote:
>
>> Michael-that is why I asked the question in the beginning, Where is the
>> fuel coming from and what is the cure for the problem? I agree that the
>> fuel is "atomized" in the throttle area and that would be the best
>> condition to send it to the engine but this car is dumping fuel and I
>> cannot find the mechanism to stop that flow. Suggested lighter nitrile
>> floats are at the top of the list, if in fact my brass ones are bum. Bill
>> Lawrence modified his intakes possibly due to fuel issues? The system on
>> this early car (same as yours) is a bit "cruder" than the revised float
>> bowl vent system (with no manifold drain?). And, I cannot see anything
>> wrong the float setting as presently set.
>> The fuel is not coming out the jet with the key off and the float bowls
>> full to proper level-it is as you said below the top of the jet. Float
>> valves are closed. Its when the key is on and fuel pressure is applied
>> that I am getting the overflow condition. I was hoping that someone else on
>> the team has had a similar experience. Hank
>> --------------------
>>
>> From: "Michael Salter" <michaelsalter at gmail.com>
>> To: "Hank Leach" <gradea1 at charter.net>
>> Cc: "Healey team" <healeys at autox.team.net>
>> Sent: December 23, 2024 at 12:21 PM PST
>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>> Sorry Hank but I think you have that wrong.
>> In and SU carb,and for that matter almost every other type of
>> carburettor, fuel DOES NOT pump out through the jet.
>> The fuel level, as mentioned previously, is controlled by the float
>> chamber float valve to never actually be above the top of the jet. It is
>> only the flow of air across the carburettor "bridge", where the jet is
>> positioned, that draws fuel up through the jet to be atomized into the
>> airflow and into the inlet manifold.
>> This is all related to Bernoulli's principle
>> <https://www.google.com/search?client=firefox-b-d&q=Bernoulli%27s+principle>
>> which is the basis upon which all carburettors work.
>> If fuel is coming out of the jet when the engine is not running then the
>> mechanism controlling the float level is not operating correctly.
>>
>> M
>>
>> On Mon, Dec 23, 2024 at 1:37 PM Hank Leach via Healeys <
>> healeys at autox.team.net> wrote:
>>
>>> Ah! A rebel in the crowd. I looked at a bunch of photos of 1953 100
>>> engines on the web. Many are configured as mine with NO FLOAT BOWL DRAIN
>>> TUBES. The *later *engine setups have drain tubes in the lid. This
>>> includes the cars using H6 carbs (Lemans). Also, on these early designs
>>> there is a different carb adaptor. Part 1B1672 which has a lower drain in
>>> the casing up to engine # 139915 (my engine 139563). Of course Moss,
>>> etc. only sell the later style products. but some books show the solid
>>> float lids and some show vented lids and some show a lid with a drain tube
>>> (air vent).
>>>
>>> So, in theory the way the early system works; fuel is inlet from the
>>> float chamber and enters the jet thru a hole in the tube positioned between
>>> the two gland washers which are to keep the fuel intact. when the choke is
>>> pulled that jet hole is lowered to send in, as the British say..."a neat
>>> petrol supply" to start the car.
>>> Now, if you turn on the key, fuel pumps in and is moved thru the jet
>>> into the throttle area and into the manifold. Unless the engine is now
>>> turning and suction from the piston is active, the fuel will run
>>> haplessly in the intake manifold and out the drain tube to the ground. So
>>> the important procedure in these early systems is turn the key and crank
>>> the engine immediately or it will overflow fuel down the drain tube.
>>> I'm here testing the operation of the carburetors in a static mode-its not
>>> going to do anything but spew fuel to the ground. Right?
>>>
>>> The later design using a float bowl vent tube also send fuel into the
>>> manifold but without a drain tube the fuel will go into the engine, as the
>>> Moss PDF described, diluting the oil and washing the cylinders. Sounds like
>>> the best method of starting up is to crank the engine as soon as you hear
>>> the fuel pump click...I typically have waited until the pump stopped (float
>>> bowls full) before cranking. Live and learn?Hank
>>>
>>>
>>> --------------------
>>>
>>> From: "WILLIAM B LAWRENCE" <ynotink at msn.com>
>>> To: "Hank Leach via Healeys" <healeys at autox.team.net>, "Bob Haskell" <
>>> rchaskell at earthlink.net>, "richard mayor" <boyracer466 at gmail.com>, <
>>> gradea1 at charter.net>
>>> Sent: December 22, 2024 at 9:29 PM PST
>>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>>>
>>> I’d like to be able to answer that, but I have to confess I’ve modified
>>> the induction system on mine (I know, I’m going to Hell) and I’m a little
>>> fuzzy on the details. If memory serves (a doubtful premise) the float bowls
>>> originally had an open vent arrangement on the top with no drain tubes. The
>>> car was built up from several dozen boxes of parts, so that may not have
>>> been correct. About 20 years ago I built a pair of H6s and installed those
>>> with drain tubes. The car is a bitsa anyway so originality is secondary, or
>>> maybe tertiary…
>>>
>>> Bill Lawrence
>>> BN1 554
>>> ------------------------------
>>> *From:* Healeys <healeys-bounces at autox.team.net> on behalf of Hank
>>> Leach via Healeys <healeys at autox.team.net>
>>> *Sent:* Monday, December 23, 2024 1:59 AM
>>> *To:* Bob Haskell <rchaskell at earthlink.net>; richard mayor <
>>> boyracer466 at gmail.com>
>>> *Cc:* healeys <healeys at autox.team.net>
>>> *Subject:* Re: [Healeys] overflowing fuel into intake drain tube
>>>
>>> Thanks Bob-yes the Moss site confirms they have alternate nitrile floats
>>> and about $20 each. Looking at the diagram there is a drawing of the float
>>> chamber overflow AUC1866 (451-250) $24.99 each. I do not have these
>>> overflows on my float bowls (as Richard Mayor mentioned their location)
>>> Instead the early cars have silver vent caps and a red washer which allows
>>> air out and those two intake manifold copper drain pipes at the bottom of
>>> the carb intakes. There is a PDF note on that part which reads:
>>>
>>> "These pipes are open to the atmosphere, for two reasons: first (and
>>> most important) they allow the fuel coming into the float bowl to displace
>>> the air in there so the fuel can reach its correct level in a timely
>>> manner. Second, if the float valve (needle-and-seat) should stick open (as
>>> they do when a bit of grit is trapped on the mating surfaces) the fuel will
>>> be piped out and down – away from the engine. If the *fuel could not
>>> escape through the overflow pipe, it would pour down the carburetor throat
>>> into the engine*. With that much liquid gasoline, not all of it will
>>> vaporize before the spark plug fires. The fuel that does vaporize will make
>>> the mixture so rich (as if the choke were engaged) the car will belch black
>>> smoke out the tailpipe. The engine will eventually flood and die."
>>>
>>> The point here is that not having those overflows on the float bowls;
>>> the overflow is actually after the throttle plates on my car. I wonder how
>>> Bill Lawrence's early car is configured and if he has float bowl overflows
>>> or intake overflows? Is it possible that this is a clue to my delima?
>>> Trapped air? Hank
>>> --------------------
>>>
>>> From: "Bob Haskell" <rchaskell at earthlink.net>
>>> To: <gradea1 at charter.net>, "richard mayor" <boyracer466 at gmail.com>
>>> Cc: "healeys" <healeys at autox.team.net>
>>> Sent: December 22, 2024 at 4:28 PM PST
>>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>>>
>>> Hank,
>>>
>>> I think the newest floats are made from nitrile rubber - nitrophyl, not
>>> plastic. Supposedly unsinkable.
>>>
>>> Cheers,
>>>
>>> Bob Haskell
>>> Austin-Healey 3000 roadster registrar
>>>
>>> On 12/22/24 17:49, Hank Leach via Healeys wrote:
>>>
>>> I actually cannot figure where all the fuel is coming from. In static
>>> mode-key off and float bowls at proper level-with dashpot and piston
>>> removed, no fuel is apparent (as Michael says about 1/8" below jet or as
>>> you say equal to float setting). However, with key on and carbs together
>>> it's a different story-fuel is flowing steadily. The suggestion that was
>>> made that we really need to have clear plastic float bowls has merit. I
>>> cannot tell if the brass float is pushing hard enough to shut off the peg
>>> on the valve. When held shut by hand its positive.
>>>
>>> If the float is "heavy", then it will not effect enough pressure on the
>>> peg to stop the flow. This is why someone suggested plastic floats instead
>>> of brass. Fuel is the shut off mechanism. I have swapped float and needle
>>> valves from front to rear carb in hopes that the front one will now start
>>> leaking. That may be a clue to the issue. Waiting for a dry day (next
>>> year?) to test that theory.
>>> --------------------
>>>
>>> From: "richard mayor" <boyracer466 at gmail.com> <boyracer466 at gmail.com>
>>> To: "Leach Hank" <gradea1 at charter.net> <gradea1 at charter.net>
>>> Cc: "healeys" <healeys at autox.team.net> <healeys at autox.team.net>
>>> Sent: December 22, 2024 at 2:23 PM PST
>>> Subject: Re: [Healeys] overflowing fuel into intake drain tube
>>> Hank,
>>>
>>> If I read your post correctly, the fuel is coming out of the jet in the
>>> carburetor into the intake manifold and then out the drain tube. Not from
>>> the overflow tube on the float chamber. I’ll proceed with this assumption.
>>>
>>> The level of fuel at the jet is the same level as that in the float
>>> chamber. That is the way these SU carbs are designed. That is why float
>>> level is so important. If fuel is flowing out of the jet before the
>>> needle valve shuts off the fuel supply at the float chamber then your float
>>> level is set too high. You need to close the float needle valve with the
>>> float at a lower level. Instead of using 7/16th as a guide, try 1/2” and
>>> see if that stops the flow. But then you said you tried different
>>> settings.
>>>
>>> Is there an obstruction that is preventing the float from rising all the
>>> way to the top to close the needle valve? Try a different float. Polish
>>> the post. Is there any wear in the fork or pivot in the casting that is
>>> not allowing the needle to move feely into it’s seat. I think that’s where
>>> the problem is.
>>>
>>> Richard Mayor
>>> boyracer466 at gmail.com
>>>
>>>
>>> On Dec 22, 2024, at 12:28 PM, Hank Leach via Healeys
>>> <healeys at autox.team.net> <healeys at autox.team.net> wrote:
>>> I have chased the cause of too much fuel exiting from the rear
>>> carburetor overflow of my 100 for years. These are H4 carbs-very simple
>>> design, but must be done correctly to perform. So I find that the jet is
>>> out of center and piston is sticking up above the flat about 1/8"-that
>>> would allow fuel to run into throttle area and out overflow drain tube.
>>>
>>> No way to center jet on car. Remove carburetor-a 4 hour job- and clean
>>> and replace gaskets and gland washers-yes cork- and reassemble and center
>>> jet...now works perfect. Re mount carburetor and connect fuel lines-another
>>> 4 hour job. Both carb pistons drop with a clunk at the same time. Turn on
>>> key- fuel pump clicking-overflow again leaking.
>>>
>>> I have reset the floats and float needles (brass) were replaced many
>>> times-that's not the issue. No fuel in float bodies-they are not leaking.
>>> I just cant believe its too much fuel pressure but then again, this is a
>>> British Car.
>>> Float is brass but when shaked it is dry. I filled the float lid with
>>> carb cleaner while holding needle valve closed and no leaking. That's two
>>> places checked (these are unfortunately "new" parts) Now the next leak
>>> could be between the needle and jet if not closed off-also new parts-jet
>>> .090. Needles are QW as specified but i also have a set of ATs which are
>>> lean that I am tempted to try. Actually both needles are about the same at
>>> top .089, but ATs are a bit fatter at mid range. Problem is all testing
>>> stinks up the garage and creates an explosive atmosphere so best done
>>> outside in the rain.
>>>
>>> I know some folks like Grosse Jets-but I don't-- I prefer the simple
>>> brass ones with viton tips which do work if pressure is applied by forked
>>> leg-also new, and set to 7/16" or MORE. With covers off, both bowls are
>>> equally about 1/2 filled. Fuel pressure is a thought as it can push by the
>>> stops but its the correct pump and when key on clicks fast then slows to a
>>> stop... but then tick, tick which it should not do! Fuel is going out and
>>> down the drain tube to my swimming pool drip pan. Im tempted to measure the
>>> top of the needles to see if they are really at .089. Can't measure the new
>>> jet but its stamped "9" Maybe stick in a number drill to see if its round?
>>> Mind you, these carbs have about 125 miles total on them. As far as I know
>>> these are "genuine SU" parts-not Moss India knockoffs.
>>>
>>> I really thought that the centering was the issue and took the carb off
>>> for that reason which cured the drop-each drops equally with thud. That's
>>> not the problem. Any suggestions? Someone says use plastic floats...Hank
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> ---------- Forwarded message ----------
> From: richard mayor <boyracer466 at gmail.com>
> To: healeymanjim <healeymanjim at hansencc.net>
> Cc: healeys <healeys at autox.team.net>
> Bcc:
> Date: Tue, 24 Dec 2024 09:56:44 -0800
> Subject: Re: [Healeys] carb damper
> On occasion I have seen dampers with plastic caps that have the steel rod
> protruding through the top of the cap. This is caused when the engine has
> backfired through the carburetors and the piston and damper are driven
> upwards. This drives the damper rod through the plastic cap. You will
> never see this with the dampers with brass caps.
>
> I suspect this is what started the issue with your damper before the
> previous owner made it even worse.
>
> Richard Mayor
> boyracer466 at gmail.com
>
>
>
> On Dec 24, 2024, at 9:02 AM, healeymanjim via Healeys <
> healeys at autox.team.net> wrote:
>
> ran into something have not seen before. cleaning the carbs on an MGTC
> and discovered there is no damper. there is a plastic cap and a 3/16 hole
> approx 1/4 inch deep in top of piston rod. Moss shows a damper and so does
> the workshop manual. any ideas what i have here?
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