New rebuilt 383.. starts well cold, runs great, doesn't start after warm

[artiststan]

My 69 Roadrunner 383 stock stick car had engine rebuilt about 100 miles ago, so it's brand new. The car starts well when cold, runs very well (like new), but once it is warmed up if I turn it off to get gas etc, it won't easily start. I tried giving it no gas, mild gas, holding pedal down and almost ran my battery down trying to start it again. When I brought it back home it smelled a lot like gas in the garage, but that was after driving it 20 miles since the last time it did not easily start.

Vapor locks are often mentioned, but I am open to where to start. It's no fun to not be able to turn the car off for fear that it will not start again. I use 93 octane gas, but have thought of trying an additive in addition, but would like to hear any thoughts any of you have for this. Thanks

 

[Ranger]

It's not the fuel.
Is the choke adjusted properly? That's the FIRST thing I'd look at.

 

[mac]

my guess is maybe the heat cross over in the intake is not blocked off so if there is space available, add a small phenolic spacer under the carb. new gas likes to boil very easy. my 2 cents.

 

[Rapid Transit]

If you are smelling gas, that sort of leads you there.
Too much someway. And or you bowl is leaking fuel and has to be refilled by turning over the engine.
But the choke?
Does this carb have a choke unloader?
Usually they are necessary when the engine is between warm and hot.
Start with the basics.
Does the accelerator pump squirt gas when it wont start?
If so.
When it won't start, go out take off the cleaner, and be sure the choke is wide open while someone tries to start it.

 

[quikbird]

I agree with rapid transit. make sure that the butterfly plate in the carb is open when you are trying to start it up. from the symptoms you are describing, I don't think it is open far enough.

 

[MOPLUM]

If you have stock exhaust manifolds, check the right manifold heat riser valve to make sure it moves freely. If stuck closed it will force hot exhaust through the intake manifold all the time. It should only be closed for a short time while the engine warms up to prevent the intake from frosting. Once the engine is warm, the spring on the heat riser valve should open to allow the exhaust to flow out the exhaust pipe, not the intake manifold. IF IT IS STUCK, it will cause the gas in your carburator to boil away after you shut off the engine, because your intake manifold will be to hot. You could also try a plastic or wood spacer between the intake manifold and carburator to help stop heat transfer. Like mentioned in one of these posts, this new gas boils off faster than when these cars were designed.

 

[metalstorm]

Turn down the fuel psi to be sure it is not getting past the needle,seat double check you are in the idle system.[you can stall the engine by turning the idle screws in all the way.]