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Fuel leak on H2 carb

Posted: Mon Apr 02, 2012 3:45 am
by 54woody
You may remeber a month or two ago I posted about Woody's choke being non-operative and how I was able to unstick the gummed up jet with a few dribbles of carb cleaner. I thought all was well, but after doing an assortment of unrelated work over the winter and with a hint of spring in the air, I was finally in position to start the car up yesterday...

The good news is that the choke seems to be working now as I was able to easily start it up without having to use a blast of quick start. The bad news is that the bottom of the jet at the adjustment nut is wet with fuel. Should I be ordering a new jet bearing kit to fix this? Is this something that can be done with the carb in situ on the car or am I better off removing the whole thing from the car and working on it at the bench? Any tips or cautions?

Re: Fuel leak on H2 carb

Posted: Mon Apr 02, 2012 9:38 am
by bmcecosse
Just nip up the larger nut around the jet assembly - the seals have dried out over winter.

Re: Fuel leak on H2 carb

Posted: Tue Apr 03, 2012 3:35 am
by 54woody
Is this the nut you meant? If so, I had a quick go at it this evening it wasn't willing to budge in either direction.[frame]Image[/frame]

Re: Fuel leak on H2 carb

Posted: Tue Apr 03, 2012 9:50 am
by bmcecosse
Yes - that's the one - great picture BTW! Well - the seals will probably swell up anyway with the fuel so I would 'wait and see' !

Re: Fuel leak on H2 carb

Posted: Tue Apr 03, 2012 1:22 pm
by 54woody
I hope it does correct itself but, if it continues to weep after a few days, the seals would need to be replaced, correct? At that point would I be needing a jet bearing kit? Anything else?

Re: Fuel leak on H2 carb

Posted: Tue Apr 03, 2012 3:57 pm
by bmcecosse
I suppose so - but a slight 'dampness' wouldn't worry me too much - as long as it doesn't drip. If so - tug a bit harder on that nut......

Re: Fuel leak on H2 carb

Posted: Thu Apr 05, 2012 6:19 pm
by JOWETTJAVELIN
You don't need a 'jet bearing kit', all you need is a new gasket set, I did mine recently and it's an easy job as long as you don't disturb the jet itself. Just make sure you soak the cork gaskets in clean engine oil for 24hrs prior to fitment.

There is a cork gasket just above the nut you point to, on mine (H1 carb), this gasket literally crumbled to dust!

See this link for my post on a similar problem to yours, I hpe you find it useful:

http://mmoc.org.uk/viewtopic.php?f=4&t=42517

Re: Fuel leak on H2 carb

Posted: Thu Apr 05, 2012 8:45 pm
by bmcecosse
These are not 'gaskets' ....... Unless dripping - leave well alone....

Re: Fuel leak on H2 carb

Posted: Thu Apr 05, 2012 9:07 pm
by JOWETTJAVELIN
Evidently it is weeping from somewhere. Leaks don't start unless something is amiss. On a car that has been laid up the O rings may have dried out and the seal lost.

Re: Fuel leak on H2 carb

Posted: Thu Apr 05, 2012 9:45 pm
by bmcecosse
When i had that type of carb there was always a small darkish stain on the tie-plate below, although I never saw it 'drip'.

Re: Fuel leak on H2 carb

Posted: Thu Apr 05, 2012 10:32 pm
by 54woody
Unfortunately it does drip while the engine is running so I think it requires attention. I will have a close look at it this weekend with the help of a friend who has rebuilt dozens of SU carbs.

Re: Fuel leak on H2 carb

Posted: Fri Apr 06, 2012 7:35 pm
by bmcecosse
You got all sorts of 'green' stuff in the fuel in Canada these days? That may be the reason.

Re: Fuel leak on H2 carb

Posted: Mon Apr 09, 2012 1:38 pm
by 54woody
Had the jet assembly apart. The big cork seal at the bottom was totally petrified as was one of the small cork jet seals. The other jet seal had all but disintegrated. We replaced the 3 cork seals along with associated washers, cleaned and polished up the other parts and reassembled. About an hours work and less than $10 in parts. Reinstalled the carb and fired the old boy up...not even a hint of dampness to be found!

Re: Fuel leak on H2 carb

Posted: Mon Apr 09, 2012 3:43 pm
by JOWETTJAVELIN
There we go... good job all round! :)