Carburetor leak

W

woodrow

Senior Member
On our 1930 Model A yesterday I noticed that when the car is parked in the driveway with the front higher than the rear the carb has a drip. When parked on a level service it doesn't drip at all. Do I need to remove the carb and put in a new gasket set or what? Thanks
 
Can't tell for sure---from the bottom. The float adjustment makes sense. I'm guessing that the float is too high?
 
How steep is the driveway? If it's quite steep this might be normal behavior. If the carb gets tilted upward so that the level of the gas in the bowl raises above the top of the main and cap jets, it's gonna leak.
 
I just fixed the carb leak on my PU yesterday. It's got a Zenith. It looked like a leak from around the float bowel so I ASSUMED (and we all know what that does) that the float was set too high (I had measured it before installing, so was flummoxed) so gas leaked around the seal. After first looking at it and before doing anything else I wiped the bowl dry and watched a small bit of gas start to leak out again. It appeared to be coming not from the bowl but from the gas line so I removed the gas line sealed it with tape and reinstalled it. Still leaking. Then I noticed that the leak looked like it might be from around the seal to the filter on the carb, so I took that off and installed another gasket. Fixed! No more leaking.
Lesson: Do some detective work to try to figure out what's happening before jumping to conclusions. BTW my more normal thing is to leap into it and disassemble everything then do the investigation after my first thought fails, resulting in extra work and sometimes extra damage.
 
RE " It appeared to be coming not from the bowl but from the gas line so I removed the gas line sealed it with tape and reinstalled it. Still leaking." The nut does not seal the joint between the fuel line and carb. It compresses the flare to carb. The nut is a compression nut only, so tape there does nothing.
 
Just worked on my fuel leak. In the past I assume the carburetor. Suspected a stuck float valve. Instead of jumping and taing the carburetor apart I checked first if my fairly ned shut off valve was leaking. I have a extra fuel filter in the engine bay, Pinched the line and the fuel leak stopped. Diagnosis: fuel shutt off valve leaking. Ordered a new one. I have learned over the years: check the simple things first. If it was not the shut off valve I would have checked next a stuck float valve. Hope this helps someone.
 
I agree with the comments about the float valve adjustment. If you look at a carb cut-a-way drawing, you will see that a 5/8 in. gas level puts the gas level right at the top of the cap and main jets. When I set the float level I try to increase this to 11/16 in. or just below 3/4 in. to prevent this "car on an uphill position" leakage. As long as the gas in the carb bowl always covers the Compensator jet, the lower bowl level will not be a problem. The other potential problem is coming up to stop signs. The throttle plate closes, gas sloshes forward in the bowl, the Secondary Well is nearly empty and there is no gas available for the Idle jet for a couple of seconds. It is a race to fill the Secondary Well through the Compensator before the car stalls. It is just the way Zenith designed this carb. Ed
 
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