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Float bowls

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go_inbroke

go_inbroke

Senior Member
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'61 TR3A
The float bowls are leaking down over night. Are the seals that connect the bowls to the carbs the ones that control this problem? #s 49 and 50 in the Victoria British catalog.
 
Either those, or the lower gland seal, #92 here
 
I was wondering could the problem perhaps be the piston needle is not down tight enough in the jet when the engine is off. I cannot rap my mine around it, but it seems to me that it could leak there?
 
I'm hoping to stop the leak without having to rebuild the carb...It might be time to buy a carb book.
 
Put some paper towels under the carbs and see where the "drips" are coming from!
 
At least that will give ya a clue what's leakin'.

But remember: Fluids will go (track) to the lowest point before dropping. Look for "tracking" too.
 
sp53 said:
I was wondering could the problem perhaps be the piston needle is not down tight enough in the jet when the engine is off. I cannot rap my mine around it, but it seems to me that it could leak there?
Click to expand...
Nope, the needle does not seal tightly to the jet even with the piston all the way down. But the fuel level should be below the top of the jet, so even with the needle removed entirely, the fuel would just sit there.

Of course it is posssible for a leaking float valve to let the fuel level rise enough to leak out of the top of the jet with the engine off. But only for an ounce or two; the bowl will still have plenty when the level drops too low to leak out of the top of the jet.
 
Bowls are dry, dry, dry...Need to crank, crank, crank
 
If the leak were at the needle, wouldn't the fuel simply run into the intake?
IMHO, the leak is more likely to be where the float bowl attaches to the carb or, as Randall said, at #92.
 
Another method of finding which seal is leaking is to start the engine (so you know the bowls are full) then shut it off. Touch the head of the bolt that holds the bowl on, if your finger is wet then it's leaking there. Touch the bottom of the jet, if your finger is wet then it's leaking there as well.

Until I switched to the O-ring jet seals from Moss, the two seemed to last about the same amount of time.

BTW, it is possible to replace both the bowl seal and the gland seal without removing the carbs from the manifold. But it involves a certain amount of working by feel, as you can't really see what you are doing. And after you change the gland seal, you'll need to recenter the jet, of course.

Someone, I forget who offhand, sells poly bowl seals that should last longer. Might have been Mark Macy or maybe it was Jeff Palya; anyone else remember? I threatened to do it myself, but never found one a them round tuits.
 
If the bowls are empty after sitting there's a leak at either the jet supply line or at the jet bottom itself (less likely). Gas don't propagate "uphill".
 
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