thanks everyone who replied to my post about mysterious hot-weather engine
flooding
I got a number of replies to this post (some may have been off list). With a
number of suggestions including: vented gas cap; cleaning the outside of the
carb especially around the bits and pieces of the throttle and automatic
choke; pulling the vent hose of the carbon adsorber; and cleaning the vent
hose out.
What all these suggestions had in common was the idea that the carb was
being flooded by fuel condensed in the carbon adsorber. I'm not sure if
cleaning the outside of the carb quite follows the same logic, but sure
enough it is pretty grimy in there and so i'm going to set to it and see if
that solves the sticky choke problem.
Anyhow, I figured that i would set about trying the vent line suggestion
(bob's) first cos it was the one that involved the least non-standard
alteration (though the most work). Interestingly, the whole system in the
boot had clearly been replaced recently (the hose, the line and the little
tank), perhaps in an attempt to solve the problem. I then checked out the
connections to the carbon adsorber, and lo and behold, there was the problem
(or at least part of it), the 8" or so of hose from the adsorber to the line
itself must have been 20 years old. It was half rotted through and kinked
back on itself. There's no way in hell anything was getting back to the tank
through that! So i'm off down to the store for a replacement. I'll take the
opportunity to blow the line through as suggested by Bob, but i'm feeling
very butch right now... ;-)
Thanks Bob! you are very very cunning.
cheers
Joe
_________________
Dr. Joseph Garner
Department of Animal Science,
University of California,
One Shields Avenue,
Davis,
CA 95616
USA
tel: + 530 754 5291
fax: + 530 752 0175
_________________
> -----Original Message-----
> From: Bob Howard [mailto:mgbob@juno.com]
> Sent: Wednesday, April 26, 2000 11:22 AM
> To: djw69@idt.net
> Cc: mgs@autox.team.net
> Subject: Re: once is accident, twice is happenstance, and three times,
> Mr Bond, is enemy action.
>
>
> Dave,
> Try clearing the vent line from the plastic cannister back
> to the fuel
> tank. If it's plugged the expanding gas in the tank
> pressurises the fuel
> line, then forces extra gas into the carbs, which then floods
> over into
> the plastic cannister. If the vent line is clear, expanding
> gas in the
> tank goes to the separator in the trunk, then the fumes
> (only) go forward
> to the plastic cannister.
> This happened to me once. The vent line in my '72 GT was
> clogged with a
> rusty, gummy, sludgy mess. One it was clear, problem
> disappeared, along
> with a host of hot-weather hard starting and stumbling problems.
> The vapor recovery system does not affect performance
> adversely; it may
> actually recover a teaspoon of gas that would otherwise evaporate, and
> may be a good thing. The quick fix is to use a vented gas
> cap or to cut
> a notch in your present non-vented cap's rubber gasket.
> Bob
>
>
> On Tue, 25 Apr 2000 16:01:10 -0700 "Dave Wood" <djw69@idt.net> writes:
> > Joe,
> >
> > My 72 B has an occasional problem right after I fill up the
> gas tank
> > and
> > drive a short distance and park in the sun. I found that the gas
> > expanded,
> > filling the carbon canister. When trying to start, it
> sucks out the
> > gas
> > from the canister and floods the engine. This can be overcome by
> > disconnecting the hose from the canister to the carb
> temporarily and
> > it will
> > start just fine. I don't know how to prevent it except to not fill
> > up and
> > park in the sun on a warm day before using up a gallon or
> so of gas.
> > If you
> > park with the front higher than the back the expanding gas will run
> > out the
> > back gas filler cap. Incidentally, this doesn't do much good for
> > the carbon
> > filter either. I usually just leave the hose disconnected until I
> > think to
> > put it back on sometime later.
> >
> > Dave
> > -----Original Message-----
> > From: Garner, Joseph P. <JPGarner@UCDavis.Edu>
> > To: 'MG list' <mgs@autox.team.net>
> > Date: Tuesday, April 25, 2000 3:34 PM
> > Subject: once is accident, twice is happenstance, and three times,
> > Mr Bond,
> > is enemy action.
> >
> >
> > >okay so we're on happenstance here now
> > >
> > >I have had the same wierd stalling problem twice now... in
> the same
> > parking
> > >lot!
> > >
> > >The car (79 MGB) starts up instantly when warm, and after turning
> > over for
> > >maybe 2 seconds when really cold. Never had any complaints. Only
> > twice now
> > >(just happened) it stalls in the parking lot at work. The only
> > difference i
> > >can think of is that it is under really hot sun (but under
> a cardom
> > so go
> > >figure). Anyway, it starts up okay, but then stalls when i let my
> > foot off
> > >the gas to change from reverse to first. The first time this
> > happened there
> > >was bad petrol smell, so i figured that i had flooded it
> and waited
> > a
> > couple
> > >of minutes and it started right up. This time no amount of coaxing
> > would do
> > >the trick. In the end we popped it into fourth gear and pushed it
> > 20 yards
> > >to get the engine turned over. pushed the clutch down and it
> > started up
> > >okay. Then it ran ran like a dream
> > >
> > >que????
> > >
> > >The air filter needs replacing.
> > >
> > >The carb seems to be running a little rich. could this all be a
> > problem in
> > >the automatic choke? Sometimes if i stop at a light
> within about 3
> > or 4
> > >minutes of cold-starting then the revs creep up to about
> 2500. If i
> > tap the
> > >gas then they rev up and then drop down naturally to about 1500.
> > Only
> > >happens just after a cold start though. can this be the auto choke
> > not
> > >shutting off properly? The engine sounds very smooth - no pinking
> > etc. -
> > and
> > >last time i checked the plugs nothing which would indicate a long
> > running
> > >fuel mixture problem.
> > >
> > >The car has a second cooling system fitted to deal with california
> > heat.
> > And
> > >i have never seen the engine temperature get above about
> 20% of the
> > dial
> > >(even on a 2 hour baking hot trip in california). I've
> been reading
> > the
> > >thermostat thread so if i understood correctly, this can't
> actually
> > be the
> > >problem right, cos the cooling system only comes on once
> the engine
> > has
> > >reached an optimum running temperature? Could it be though
> that the
> > air
> > >coming into the carb is too warm for the amount of choke? or have
> > i got
> > >this all arse about face?
> > >
> > >any comments much appreciated
> > >
> > >cheers
> > >
> > >Joe
> > >
> > >___________________________
> > >
> > >Dr. Joseph Garner
> > >University of California
> > >Department of Animal Science
> > >One Shields Avenue
> > >Davis
> > >CA 95616
> > >USA
> > >
> > >Phone: (530) 754 5291
> > >
> > >
> > >
> >
>
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