Carb drains fuel into intake

[scamp340]

I have a Holley 650 double poumper with a Proform milled throat main body, an AED milled shaft and thinner butterflies throttle body. After I had a hard time idling this combination I purchased Quick Fuel Technologies metering blocks for four corner idling because I was told I needed a four corner idling set up. Now the car runs great. What I've noticed is after I shut it off, about three to five minutes later fuel runs out of what I think is the transfer slot onto the butterflies and into the intake manifold therefore making it difficult to start the car. When looking down the carb after five minutes the butterflies are soaked in fuel. It's OK if it sits overnight because the excess fuel evaporates. But if I try to start the car a few minutes after I shut it down, it is very difficult. If I try to start the car seconds after shutting it down, it starts fine because it has not started draining yet. Only the primary fuel bowl drains, about 75% of volume overnight. My floats are not set too high, I don't have perculation problems, my fuel pressure is not too high, and no parts are warped.

 

[69signetv8]

My guess it's a:
*stuck needle/seat (most likely)
*mis-adjusted float (2nd most likely)
*Too high fuel presure (very unlikely) :read2:

 

[scamp340]

No the needle is not stuck, and the floats are dead level within the float bowl. The carb drains fuel back into the intake from the transfer slot over the butterflies after the motor is shut off and there is no pressure coming from the pump. It's also not boiling since the engine is not hot enough.

 

[C130 Chief]

Bad power valve?

 

[1968FormulaS340]

Call Holley, thats what I do.

 

[redfastback]

i second the bad power valve. what # is it anyway?

 

[scamp340]

Funny how you mentioned the power valve because that was one of the things I was going to check this weekend when I was going to go over the carb. It is new, about two months old and a number 4.5. Other things I will look at this weekend are the metering block gaskets; also new and the main body gasket - new as well.