Starting problems when hot.

[Hawkdoc]

Ok, the setup. 302 with RV cam, TA470 carb, longtube headers and a C4. The problem I am having is restarting when the engine is hot. She starts fine cold and will start after setting for about 20 to 30 minutes. It rolls over fine but just won't hit. Has a new starter and mech fuel pump on it. Suggestions on where to start?

Thanks in advance
hawkdoc

 

[blubuckaroo]

Is it flooded? If your fuel level is too high the gas can perk over into the intake manifold when it's shut down. Fix it soon because this gets liquid gasoline into the cylinders. Dilutes the oil, and washes oil from cylinder walls.

 

[Hawkdoc]

Gas is at the bottom of opening on the front bowl. According to info on the Holley that where its supposed to be.

Hawkdoc

 

[Dogdare]

Vapor lock? Check the routing of your fuel lines, and make sure they are as far from heat sources (headers) as possible. Also, you don't mention if you're using a phenolic (sp?) spacer between the manifold and the carb. This helps raise the carb fuel bowl away from the heat.


Herb

 

[Hawkdoc]

tried the riser block with no improvement. I have the fuel line routed as far away as I can and have it wrapped in heat shield as it passes by the header.

Hawkdoc

 

[blubuckaroo]

I've seen capacitive discharge type ignition systems help with hot start problems. Wet plugs provide a short circuit to ground. Enough amperage and the plugs are forced to spark.

 

[Hawkdoc]

I will pull a plug today after I run it and see if they are wet when it won't start.

Hawkdoc

 

[eds66bronco]

i know you probably tried this already but clean the terminal and cable clamps and connectors on battery cables/starter solinoid. I just went through this last fall. Started up great cold but once i shut it down, it would crank but not fire. wire brushed the terminals with one of those wire brushy things and whama - bama!

 

[Tasty Geezer]

I recently had this same problem. I had installed a new fuel pump and edelbrock 600cfm carb. started awesome when cold, but wouldn't start at all when hot until I let it sit for about 30 min.

The final outcome of the solution was that my new fuel pump was pumping 12 psi. The carb was only able to handle 5-6 psi. I ended up getting a fuel regulator and set it at 5 psi. Now no matter hot or cold she starts right up.

check your specs on your carb to see the suggested psi. and then check your pressure from your new fuel pump

 

[Hawkdoc]

Was doing it with my old mechanical pump also. I will check what the new one is rated at and check with Holley also today.

Thanks again with ideas.
Hawkdoc

 

[tml]

If it's electronic ignition.. Could be a faulty inginition box.?? I had the same type of problem the culprit was the box.