Great cold start but POOR hot start - ??

B

Bruno

Member
Have a 1952 F1 with a Pertronix 6 volt ignition system (coil and "distributor") - will fire right up cold on just a crank or two; runs great. Shut it off for a few minutes after running for half hour or more trip and it does not want to start - cranks and cranks!! Thought it might be vapor lock problem but it will kick in using 2nd gear very easy. What are some of the probable causes for this???? Thanks!!!
 
Check for spark when cranking cold and check again when the problem occurs. It could be a problem when the coil heats up or low voltage to the coil. Low battery, bad connections or dirty ignition switch. When you tow the vehicle you get whatever voltage the battery has to offer. When you use the starter you get a lower voltage due to any bad connections or low battery. G.M.
 
Coil, gets hot, resistance increases, voltage decreases, and with 6 volts, not much room to spare. As GM suggests, the connections must be clean, and your cable from the battery to the motor should be a #1 or #0 cable. Check your grounds, all must be clean and mechanically sound.
 
I just fixed a 48 fordor that had been having that problem for years. What his was doing was the oil bath air cleaer was restricting the carb so much it was choking it and causing it to flood automatically. I loosened the sinch bolt on the air cleaner and ran the engine at a low idle, then while listening very carefully lifted the cleaner and the engine instantly ran better. I switched out his original oil bath for a small paper hot rod filter and the customer couldn't be happier. The engine has more power and he has yet to have the problem again. I also installed an inline electric fuel pump but that only raised the pressure by 1 psi so that was not the real issue.
 
Does it start nice and easy without any choke? If so it may be over rich, Like as if the choke is on. Then when it's hot it doesn't want to start on this over rich mixture. Had it happen once when the float was failing.

Mart.
 
Bruno. I had the same problem about a month ago. Same exact problem. Start up cold and run great until I shut if off then it would not start. It didnt matter what I did it just would not start with the battery & starter. Pull it and it would start or just let it cool off for and hour or so and it would start. I had the carb rebuilt didn't help. Had the distributor rebuilt dint help. I bought a new coil for it (modern style) didn't help.I was about to put a for sale sign in the window. I was told by some of the Ford barners to try a rebuilt coil by Skip Haney. So I figured what the heck nothing else has worked. Bought one installed it and have not had a problem with it sense. I drove my car 140 mile round trip a week ago and never had one prob with it. She starts right up now. So my advice to you is do the same. If your running a modern style coil get rid of it and talk to Skip about buying one of his coils you wont be sorry.
 
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