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Hard Starting when warm

Posted: Tue Jul 05, 2016 11:49 am
by aforests
Restoration is pretty much complete and I have been doing quite a bit of driving and runs really good. (all stock)

Really the only problem I have is after driving around and all is warm, I shut it off and if it sits longer than 5 minutes or so, I have to crank for at least 5-10 seconds to get it to start. It will eventually start, but is stubborn. When the jeep is cold, it starts right away.

Does this sound like Vapor lock? When I installed the fuel line to the carb, I routed it away from the manifold per TB 9-804-6

Any ideas?

Posted: Tue Jul 05, 2016 1:48 pm
by Bobber
I kinda have the same problem. It seams like it floods. I have to open the plugs I put in place of the fuel primer nozzles. Then it fires right up. Other than that, it starts up every time.

Posted: Tue Jul 05, 2016 7:56 pm
by wesk
Try looking at more possibilities.

Timing if too advanced results in more difficult starting after the engine sets and heat soaks awhile.

Over advanced timing is also tough on the starter during hot starts.

A lack of venting of the distributor housing will lead to overheated coil and hard hot starts. Did you forget to connect those two vent lines?

Coolant temps above 180 have a tendency to boil off the gas in the carb bowl on the M38A1/M170.

Posted: Wed Jul 06, 2016 3:53 am
by scoutpilot
One more I have found. Do not pump the pedal on a warm restart. Just press in the clutch pedal, key on and engage the starter.

Posted: Wed Jul 06, 2016 7:31 am
by aforests
Thanks for the suggestions. Vent lines are all correctly attached to the distributor.

I will check timing again to see where I am at.