Hot Starting Problems

[Roger Frazee]

I need help. My '47 Pontiac six will not restart when the engine is warm. It will crank forever, but will not fire. I have to let the car set for five to fifteen minutes before I can get the engine started again.

It starts perfectly when cold and runs great.

To date, I have tried the following:

Rebuilt the WA1 carburetor and experimented with several float settings. The float is now set according to the Pontiac Shop Manual.

Set the anti-percolation valve to factory specs

Checked for flooding by removing a spark plug and checking for gas. The plug was bone dry.

Added an aluminum heat shield to the existing heat shield to keep heat away from the carburetor bowl.

Changed the after-market fuel filter

I am at a dead end and would appreciate any advice offered.

Damn the Torpedo

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[Guest GaryP5]

This is a long shot but it happened to me so I thought I would pass it on. I also rebuilt my carb this past winter. Got it all cleaned up and then sprayed each piece with Carb Renew from Eastwood paints. Used a rebuild kit from Cal Pon Res and it looks friggin' awesome. Installed it and then had weeks of nothing but trouble with it, especially on hot days. Finally I found the problem. It was the tiny bits of tape I had placed over the bowl vents to keep out the carb renew. When it was painted over the tape became invisible. The inability for the bowl to vent led to all my troubles. Check your vents, again... this is a long shot but I thought I would pass it on for anyone else who might make the same bonehead mistake that I made.

[Guest GaryP5]

Found a pic showing the nice painted flat spots where the vents should be.

[Roger Frazee]

Thanks for the tips and the picture. I will make sure all bowl vents are clear. I suspect the problem will turn out to be something simple. It's just a matter of finding it before losing my mind.

[Guest GaryP5]

A couple of things to think about... you mentioned an aftermarket fuel filter. My Pontiac fuel pump only puts out 4 lbs of pressure to pull the fuel from the tank. It's possible that your pump is struggling to pull fuel through the filter even when it's clean. I installed one a few months ago right outside my tank as it was filling my fuel bowl with rust. I had vapor lock/ hard starting like crazy afterward. I could tell it was a pressure problem as the fuel level in my water separator glass bowl would be somewhat low. I then resealed the fuel tank (eastwood has a kit) and pulled the filter, no problems since. Have you checked to see what volume of fuel your pump is pulling? One easy trial would be to temporary pull the fuel filter and give it a shot. It might be the solution... or it might not.

[Roger Frazee]

That's a good thought. The filter is between the pump and the carb, so replacing it with a piece of hose will be easy. I'll give it a try.

The fuel pump is new. I replaced it last fall because the old one was leaking.

Thanks for the suggestion.

Damn the Torpedo

[Guest Fitz]

All the advice above are very good, but to me I think it's the ignition coil your problem.

It's a problem I saw quite often on old car and lift truck. It's not cost a lot to try a new one if your suspected gaz problem don't cure your engine.

good luck.

Fitz.

[Guest Mr. Lang]

Checking the coil is a good idea, don't ask how I know this. My 1950 Chev truck had a hard time starting when hot, and it was weak spark. My starter needed new brushes, and was drawing too much current. The brushes were oil soaked. I replaced the coil as well, probably overkill, but I've put on seven thousand miles since.

Also, when my car is really hot ('49 Pontiac), it likes to be cranked over for a few revolutions, then a bit of gas pedal, and she starts right up. I find that the gas really tends to percolate into the manifold, and floods it.

I have also learned, that when I come off the highway on a hot day, and shut the car off, like at a gas station, it really helps to open the hood while I fill 'er up. Otherwise it sometimes vapor locks.

Full speed ahead!!!

[Guest]

When this engine is hot and you've pulled the plugs (and you say they are dry) and you crank the engine and you've got spark and you look down the carb and you do a wide open throttle check do you see a nice good squirt from your accelerator pump??

Don

[Roger Frazee]

Thanks to all for some very good tips. Fitz, however, wins the prize. The problem was the coil.

I hated to remove the original coil, complete with armored primary wire, but the new coil did the trick.

She starts first time, every time now.

Thanks again for the advice.

Not Damning the Torpedo anymore.

[Guest GaryP5]

That's great news. Ive heard of some people who have relocated their coils to the firewall because of overheating. That might be an option for you should your new coil get fried. Also... if the original coil is a "looker" you could always keep it for show purposes doing a quick swap before and after shows. Either way... good to hear your Torpedo is up and running. Cheers!

[Guest Fitz]

Cool to know your Pontiac reliable now.

Fitz.

[Roger Frazee]

"Reliable" might be a strech at this point, but I did drive her 80 miles today in 91-degree heat. She never missed a beat.

[32Pontiac6]

Had exactly the same problem with my '32. Worked and tinkered and played with it until I decidted to try a new coil. Installed new coil and it starts right up every time..hot or cold.

[Guest avitia1]

by any chance do you know anyone in Oregon that is working on 1942 Pontiac or any from 36-46. i have a 1942 Pontica my self and would like to see if they can share any guidce, my car has been sitiing for 30 years before i bought it,with 46k original miles.