[Mgs] Carbs still being nasty

[Robert's New iPad]

Hi Clayton,
   Where are you? We might be able to find a friend you have not met, someone who can give you a hand with this, in the NAMGBR directory.
Bob

> On Dec 30, 2016, at 4:52 AM, PaulHunt73 via Mgs <mgs at autox.team.net> wrote:
> 
> Firstly if you can't wind the jet up past the bridge there is something wrong with the jet installation which won't help the running.
> 
> "with some tinkering of bowl valve, I was able to get the fuel right up to the bridge."
> 
> That's way too high, although if the overflow/vent port of the float chamber is blocked fuel will be pushed out of the jet by the pump.
> 
> "but lifting the piston causes it roar away and not stop."
> 
> That's not right, it's only opening the butterfly that should make it roar away, just lifting the piston (more than 1/32") should make it stall.
> 
> "currently, I have the nut screwed up all the way."
> 
> Again not right, although it really depends on just how much below the bridge it actually is.  If you think the other carb is OK compare jet heights with a depth gauge.
> 
> "The pin makes no difference, lifting the piston some increases speed for a bit and then dies."
> 
> How high is 'some'?  How long is a 'bit'?  If a very brief increase with a 1/32" lift then fall back that is about what it should be.  All the pin does is lift the piston, so lifting the piston by the same amount with the pin or with a probe in the intake should produce the same result.
> 
> "Never could get it to move no matter the speed."
> 
> Maybe your ball is stuck.  Does it move if turned upside down?  These air-flow meters usually have an adjustment to vary the size of the intake - small at idle, larger off-idle, to get the ball somewhere near the middle of its travel.
> 
> I think you are about at the limit with what you can do with this, and would be better off taking it somewhere that knows these carbs.
> 
> PaulH.
> 
> 
> 
> ----- Original Message ----- From: "Clayton Kirkwood via Mgs" <mgs at autox.team.net>
> To: <mgs at autox.team.net>
> Sent: Thursday, December 29, 2016 6:38 PM
> Subject: Re: [Mgs] Carbs still being nasty
> 
> 
>> 
>> The rear carb seems set properly. I was able to get that little increase
>> with the lift of the 1/32 pin lifter. The front carb has been more trouble:
>> screwed all the way in, I can't quite get the jet up all the way to the
>> bridge, but with some tinkering of bowl valve, I was able to get the fuel
>> right up to the bridge. It runs smoothest when rich, but lifting the piston
>> causes it roar away and not stop. So currently, I have the nut screwed up
>> all the way. The pin makes no difference, but lifting the piston some
>> increases speed for a bit and then dies.
>> 
>> I found my sychrometer on the front of my cabinet where I put about 10 years
>> ago. It is an airflow tester with the little ball which is supposed to go up
>> to the middle of a clear tube. Never could get it to move no matter the
>> speed.
>> 
>> I finally got the sound the same through the tube method. We'll see. In
>> doing all this, I looked over and saw a tiny stream coming out of the
>> radiator. Urrrr
>> 
>> Clayton
>> 
>> 
>> -----Original Message-----
>> From: Eric J Russell [mailto:ejrussell at mebtel.net]
>> Sent: Wednesday, December 28, 2016 11:53 AM
>> To: mgs at autox.team.net
>> Cc: crk at godblessthe.us
>> Subject: Re: [Mgs] Carbs still being nasty
>> 
>>> I have no idea which kind of SU's I have. This is on a 62A. How am I
>>> to tell?
>> 
>> Original MGA carbs are H4. It is also possible for them to be replaced by
>> MGB carbs - HS4 or HIF4. (HS = H type, seperate float chamber, HIF = H type,
>> internal float chamber, the number 4 is a measure of the throat diameter - 1
>> inch plus 4 eighths of an inch - 1 1/2"). Pictures of many SU carbs are
>> available on Joe Curto's website: http://joecurto.com/carburetor-library
>> 
>> For almost anything knowable about the MGA (and most of it also applies to
>> the MGB) see Barney Gaylord's MGA Guru Tech Pages.
>> http://www.mgaguru.com/mgtech/
>> 
>> For info about the MGA's H4 carbs see:
>> http://www.mgaguru.com/mgtech/carbs/carb.htm
>> For tuning info: http://www.mgaguru.com/mgtech/carbs/cb130.htm I like the
>> little tool kit shown there. I also have an SK Synchrometer (measures air
>> flow). After using the pointers to synch the carb I've used the synchrometer
>> to double check and always found it spot-on.
>> 
>> Eric Russell
>> Mebane, NC
>> 
>> 
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>> 
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> 
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> 
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