The Stovebolt Site Forums The Parking Lot '60-'66 Trucks Help! Leaky carb.

Hey all.

I came across a problem today and that would be that my carb. leaks like a sieve! And I am at a lost on this one

Some background. The carb. In question is on my 61 Chevy c-10 stock motor and brand new carb. (Rebuilt single barrel rochester) and new fuel pump(manual with electric wipers) I also have it running on a external fuel tank(small 1gal. Container with a fuel hose and filter running to the pump)

The problem, after starting up the truck the carb starts to leak from around the throttle linkage(and not a small drip or too, it's a fast leak!) so my thoughts are that it's getting to much fuel in the cup and over flowing? Is that possible? If I shut off the fuel the engine keeps running( I am guessing from the fuel in the lines/ carb. Cup) engine runs, starts to run faster then begins to die so I turn the fuel back on and the leak starts again.

Any help on this would be really really great! I can post a video if that helps too

Thanks again
-Tim

Tim,

Did you rebuild the carb?

It sounds like the float level setting is wrong.

The only way it can do this is fuel getting by the needle & seat. It can be caused by dirt in the seat, a bad float, or as TC says an improperly set float level, or too much fuel pressure.

Hey guys that's for the reply.

I did not rebuild it myself, I got it of rock auto.com. Is said that it came pre adjusted but I am sure in shipping it could become un-adjusted. Also with dirt I always run it with a paper filter so if dirt is getting by is there a better filter I can use?

I am guessing the plan of action would be pull apart, clean, adjust and if problem continues buy a regulator of some kind? Also I have tried looking around but can't find the listing of the fuel PSI for this truck, anyone know what it runs around?

The 1961 235/261 fuel pump was rated at 3.5-4.5 psi.

I think that 3-7psi would work fine without a pressure regulator - let's see what others say.

Update;

After pulling the carb. And cleaning, and adjusting ( was within factory specs) I reset the float level a little higher. After re-instal it was still leaking so I put on a pressure regulator and set it for 3.5 psi and seems to be running fine with no more leaks and took her for a drive today. Only thing going on now is a slight rough idle and if you hit the brakes hard she dies.

Thanks all for the help

Like your freshman science teacher taught you, isolate only one variable at a time.

I think the the pressure regulator was unnecessary but it didn't hurt. More than likely your float was set right from the factory but had some dirt in the needle/seat or it was stuck open. The problem you're having now is that your float level is too low and when you hit the brakes hard the gas is sloshing to the front of the carburetor bowl and starving the engine of fuel. Try taking it back apart and setting the float level to factory specs and see if that helps.

I have the adjustment data table right in front of me at the moment. Your float level should be 1-9/32" which is measured from the gasket surface to the bottom of the float in the "closed" position. In the "open" position it should hang down 1-3/4"

Hope this helps amd let us know how ya make out

Sounds like a plan, I'll be working on that this weekend after I get a new battery(mine was stolen right from the truck!) I will post a update on how it goes

Thanks again for all the help!

Also, carry a fire extinguisher.

Using TC's info: anything over 4.5psi is absolutely a NO NO. Agree with reset float, AND the drop, to specs. As has been said by several, carbs leak there for several reasons: Over flow from bowl, too much pressure, float leaking/sinking. Hope your "new" fuel pump is not an electric you forgot to tell us about. The correct stock mechanical pump would not need a regulator. I actually have never heard of a regulator on a carb engine with mechanical fuel pump.