I have a strange starting problem that I can't seem to pinpoint. The car starts great when cold, 1 pump and fires right up. It will start right up if it sits for only a few minutes. Car runs great, no hesitations or any problems.
The problem is that if the car sits for 30 minutes or so after being warm, it is hard to start. I usually have to hold the pedal to the floor to get it to start. After it starts I need to feather the throttle for a few seconds and then it will idle ok and run fine. Get a lot of black smoke when this happens. I am sure that it is flooded when this happens but don't know why. I noticed that when I shut the car off, that fuel was bubbling in the inline filter just before the carb.
I do not have a cable set up to the manual choke. Here are the specs on the motor and what I have done so far. 350ci, 3310-2 Holley 750. Fuel Pressure set to 5psi. Set floats dry to holley specs. I have also checked the floats when running and approximately 1/16 below site window. Timing set to 8 degrees advanced (base timing). 72 main jets, 6.5 power valve. Idle set at 750 RPM in drive. Using #2 hole on brown (plain) pump cam.
Anybody have any ideas?

 

Your fuel is getting hot.... either the lines run too close to the exhaust, or heat is getting to the fuel pump from the block.

Put an extra fuel pump plate blockoff gasket in it, and an extra fuel pump gasket. Move the fuel supply lines away from the exhaust, or put some kind of heat shield between them. get the line from the pump to the carb to where it's not touching the block. Anything you can do to insulate the fuel system from heat, will help.

 

I am running the stock TBI fuel pump in the tank with a Mallory 4309 Regulator. I also am using the stock fuel lines all the way to the regulator which is mounted with a bracket on the back of the alternator. The only place I can see the line coming close to the block is right before it goes into the carb on top of the manifold. I might try insulating it there. Thanks for the suggestion.

 

What type of regulator?

If a normal, inexpensive dead-heading type, you're doing two things: 1) Keeping the fuel in the "hot zone", and 2) killing the in-tank pump - they're designed to have a continous flow to keep them cool.

If you have a return style reg, never mind...

 

It is a Mallory return style regulator.

 

Update on problem. Checked it tonight after work with the hood up and air cleaner off. It sat for 40 minutes. Tried to start it and it started after cranking a few seconds but gas started shooting out of the air bleed tube on top of the carb. Is it possible that the fuel pressure is still to high? The car runs great other than this problem. Smells a little rich though.

 

Gas shooting out the top of the carb = fuel is too hot, it's boiling

How hot is the fuel line while this is going on?

Could it be that the carb itself is too hot?

 

Bumping....

I too have a hot start issue. Will crank but not fire after it has reached temp.

Held the pedal to the floor last night (when the motor was hot) and it finally fired up then idled like normal.

Carb is not very hot to the touch...fuel lines runs close to the drivers header, however. Is this a possible cause? (cause of what!?!)