Danny  I had the very same problem  it turned out to be the wrong carb for a 312 y-blk  changed to a 0-8007 350 cfm and my problem went away checked into holley and that is the carb they recommend and with vaccum secondarys the carb I tried was a 4160 600 cfm  and it did exactly the same thing   Shakey Pete

I can't answer the quality issue as I've not tried a Holley in several years. They had issues with the last management team including warped bodys and metering blocks. Fixing that problem has been addressed in this blog.

 The bottom line one this is that we all believe you're getting raw fuel leaking/dripping into the intake. We have all experienced the same thing at one time or another. You will need to find out where it comes from and fix that.

 Another thing, that no one has mentioned is heat. If the car is only used in nice weather, think about blocking the crossover passages in the intake manifold, and adding an insulator gasket or two under the carb to prevent the intake from cooking the carb. That will also help the situation.

Frank/Rebop

Bristol, In ( by Elkhart) 

Do the new Holley carbs have these bugs out of them or are they more dependable now.  Dave

SE Wis

Most off my hot restart problems are from the fuel boiling in the boil after shutting the motor off on a warm day.

I think the newer fuels boil easier.   They used to have summer and winter blends of fuel in the past.  No need for different blends as most all cars on the road today are fuel injected(remember the zinc in the oil for flat tappet cams).

I thought at first it was a needle and seet issue, as it would work again after pulling the top of the carb of and cleaning the needle.    That was just enough time to let the fuel cool, let everything dry out and it would start finally after a bunch of cranking.

I dicovered this was the issue, after beating on it in town and stop and go traffic, the carb would heat up due the supercharged air on a hot day a could actually get it to boil over at the next intesection stop.  I could not get it to restart with out shutting off the electric fuel pump, and a bunch of cranking.   I now can tell when it is about to boil over so I reach over and shut off the electic pump until I feel it clear out and avoid heating up the air chargeby driving nice for a bit.   My fuel system has a return line which helps keep the fuel cooler, but the heat is at the carb is the problem.  I also have a phenolic carb spacer and blocked crossover passages on the intake

I had issues with restarting my car after leaving it sit about tne minutes and trying to retart on hot days.   Once again the heat sink from the engine to the carb cause the fuel to boil over and flood it.

Recently my T-bird with a 460 will occassionally have a boil over start condition after shutting it off on a hot day.   Fuel related as well.   The needle and seat cannot hold the boiling fuel.

Pat Fleischman

The experts here have already given the most likely sources of the problem, whether it's power valve, out-of-adjustment choke, float or needle valve/seat. Some other small tips you might consider...depending on how long it's been or how familiar you are with your own carb and linkage, taking a digital photo or two from a couple angles can often save time by making reassembly easier. Generally speaking, isolating one issue at a time helps when trying to pinpoint the cause. Keep plenty of rags handy for when you pull the bowls. Suggest starting your trouble shooting with the power valve because that's an easy 1-for-1 swap-out. It's also not a bad idea anyway to pull your Holley apart and carefully clean, remove varnish from bowl area, replace the gaskets, etc.  Prior to re-starting, feed a bit of clean gas back into the bowl through the sight-level hole so you don't have to crank as long. Good luck.

Power valve is my guess. I've had this happen on many carbs. Shows up the worse on hot re-starts. Let them sit and cool down, start right up. Best thing is you can buy them without getting a rebuild kit.

Ol'ford nutCentral Iowa

56 Vic w/292 & 4 spd.

Depending on the age of the carb there are a couple of things that can be going on and most have been touched on by some of the other forum gents.

1. Choke not fully open

2. Float level to high. I run them just below the sight plug with the engine hot . My test is to bump the fender with my leg with the sight plugs out , a little bump answered by a little slosh from the plug and I call it good

3. The next thing is a little problem that I have encountered with older Holley's. That would be an internal leak when they are hot which causes gas to dribble down the throttle bores and flood the motor as it sits. This is usually caused by a poor seal between the metering block and the carb body. A poor casting or an older carb that has had it's float bowls repeatedly overtightened can cause this condition. The fix is easy and a standard part of any Holley rebuild for me. Lightly clamp the carb body in a vise and run a large flat file across the surface that the metering block gasket seats against. If the outer portion of the carb body shines up but the area around the main well (big hollow space in the center) doesn't then you have some warpage and possibly a leak. I generally run the file back and forth , side to side and bottom to top until I get some shine around that main well , now you know your gasket will seal that well. This may all sound crazy but the info came from Holley and it has fixed several hot start problems especially with dual quad FE's running 1960's era Holleys. This only needs to be done on the metering block side, the secondary side has a smaller metering plate which seems to not experience this problem.

Pete

The only time I've experienced this was during the summer and with the mechanical fuel pump.


Lawrenceville, GA

Is it a manual choke or the black circular plastic housing containing the bimetal spring.  That's the most common and most are electric.  Make sure the adjustment is correct by loosening the three screws slightly and turning the cap until the choke butterfly just closes and add a very small amt of spring pressure, depending on your climate, and tighten the screws.  Also make sure you have a GOOD source of voltage for the heating element and also a GOOD carb ground to complete the circuit.  As a test to see if this is your problem, you can adjsut the choke wide open when the engine is cold.  On a reasonably warm day, start it (might have to finesse it a little) let it warm up and then go for the normal drive you take and see if it starts back up.  If it does, it's probably the choke adjustment.  Also make sure the floats are adjusted properly by removing the sight plugs on each float bowl.  With the engine running and warm the fuel level should be just at the bottom of the opening. (remember safety for possible fire)  Some people like it to dribble out a little, I don't.  Holleys have externally adjustable floats and can be adjusted from the top of each bowl.  There's tons of info on the net as well as cheap books available that can make you infinitely familiar with these carbs.  Good luck.

I’ll put a leaky power valve at the top of the list.  It can possibly be either the gasket behind the valve or the valve itself has a bad diaphragm.  The easy check is to remove the sight plug from the carb 3 hours after the engine has been shut off and look to see if the fuel level is significantly lower than the bottom of the threads.

Lorena, Texas (South of Waco)