Hot Start Problem

[blown240]

This is on a 66 GMC with a 305 V6, 2bbl carb. It has new Cap/rotor/coil/wires/ and petronix box. The carb was rebuilt about a year ago. Also new fuel pump and sending unit.

When my truck is cold it will start instantly, choked or not. But once it get warm, its tough to start. It will crank for 10-15 seconds before anything and then when it does fire, its tough to keep going for the first 10 seconds. After that, it runs perfect, though the idle is a bit high.

Any thoughts? I am assuming carb, but am not sure.

Thanks

[63 & 64 Bowties]

does it crank a little slower when it's warm? Could be the timing's off.

[SS317]

I agree with the timing, especially if you just changed out the cap/roter and such. A slight bump when working on all of that could have just taken you out of timing.

When I have problems come up I try to look where I was just working first, then work from there. Usually I'm the one that did something.

[neto]

Just make sure your carb is not flooding (Do you see black smoke out the tailpipe when is does start after it's hot?) and also your starter is getting hot. Make sure it's grounded well.

[TagMan]

I had the identical problem on my '63 short wide. I found the ground strap from the frame to the block was corroded and making a lousy ground. I replaced the strap and sanded the mounting surfaces on the frame & block to bright metal and never had another problem with it. Starts great now, hot or cold.

I also had a similar problem once on my '37 Chevy coupe. The problem there turned out to be a bad 6v coil. It was a NOS coil, in the box, so I didn't suspect it at first, but all my checks pointed back to the coil. Replaced the coil and never have had another problem.

[blown240]

I dont see any black smoke, but it could be flooding. I will check the ground strap and the timing. Thanks for the tips.