Fuel Percolation

Phred

Phred

Senior Member
After shutting off the engine after a good run, I can see fuel continuing to flow/ooze from the squirter tubes into the venturies of my single downdraft 97 carb. This, of course, contributes to the "gassy" smell in the garage that Mrs. H. dislikes.

Car has electric fuel pump (2.5 lbs pressure), engine block, aluminum intake manifold, and carburetor body are all hot to the touch a few moments after shutoff. I suspect that these parts are not as hot whe the car is running because of the effect of air movement under the hood.

Will a phenolic spacer (insulator) between the carb and intake help with the percolation? Any other ideas?

thanks in advance.
 
Check out "Carburetor Cough" elsewhere in this forum. Aerocraft has a fix that might work. Good luck.
 
Phred: It certainly is a possibility that a insulator would help. It is an easy "fix". If you are in the Naperville area, I may have some material left over that you could have and I do have gaskets for the '97' as a result of fooling with flatheads. I'll check tomorrow to see what I have remaining. Also, McMaster-Carr has the material and it is quite easy to order from them through their website. Try www.mcmaster.com.

Also, I recall some downdraft installations that had a flat plate shield in addition to the insulator. The shield was quite large and acted as a heat baffle. Gar Williams
 
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Don't know if it's still feasible with your setup, but the quick fix with regular A's is to shut off the gas shut off valve for a minute or so before you turn off the motor. Better yet, just let it idle until it drains the fuel bowl and the engine dies. The problem is thermal expansion of the fuel in the bowl until it overflows the jets. It smells like the carb is leaking but it's not really. Maybe a separate shut off switch on you fuel pump could accomplish the same thing.

Steve
 
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