Holley carb help fuel leaks and floods

[68is4me]

I am about ready throw this piece of junk in the trash.

I am just trying to help my boss out. But I got suckered in to helping him out. He has 71 c10, 350 330 hp gm turn key crate motor. The carb is a holley 4160 vacuum secondary, elec choke, 600 or 650 cfm don't remember for sure.

The problems, cold start will fire right up. After warmed up turn the engine off and fuel will start dripping out the secondary throttle shafts onto the manifold. I looked down the secondary side when this happens and I can see the throttle blades getting wet with fuel. Then try to restart and starts hard due to flooding out.

What I have done: I am no holley expert but know basic carb work. I have double and triple checked float levels. Front float is at sight plug. Rear float is 1/8 below site plug. I have put new gaskets set in, and new needles in. The only thing I did not replace was the power valve and the accelerator pump seals.

This carb on the secondary circuit does not have a metering block, just a plate. Could the plate be warped. The carb leaks the same before and after rebuild.

Sorry for the long winded write up, but does anybody have any ideas what to check.

[Redline novdog]

Might want to try a phenolic carb spacer to keep the heat away from the carb. Sounds to me like it's boiling the fuel.

[68is4me]

Originally Posted by Redline novdog

Might want to try a phenolic carb spacer to keep the heat away from the carb. Sounds to me like it's boiling the fuel.

I have thought of that, but this just started happening this year. The owner has been driving it for at least 5 years and with no leaks. So I don't think a heat problem should have just started now. But I guess it's worth a try.

[geezer#99]

Try lowering the front float. Just below the sight plug. You could be carrying fuel over thru the transfer tube. Just enough to flood.
And fwiw a carb spacer doesn't help much with a holley. You need a heat plate like this.
https://www.holley.com/products/fuel...s/parts/108-70

[RichardJ]

From another thread.

"To check the power valve, put your finger over the front bowl vent with the engine idling - if it takes several seconds for the engine to die, the PV is OK; if it dies almost immediately, the PV is leaking. Plugging the bowl vent forces fuel into the engine by way of the PV vacuum passage; if the PV is good, the fuel will be forced out of the boosters to stall the engine and this will take several seconds to occur."

[the idiocracy]

Originally Posted by geezer#99

Try lowering the front float. Just below the sight plug. You could be carrying fuel over thru the transfer tube. Just enough to flood.
And fwiw a carb spacer doesn't help much with a holley. You need a heat plate like this.
https://www.holley.com/products/fuel...s/parts/108-70

I agree, it sounds like your floats are set to high. Lowering it should fix your issue.