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Discussion Starter #1
This problem has been happening for a while now and I am finally sick of it. When my car is cold, it starts right up. But when it gets all hot and has been sitting for a little bit, it won't start. The starter will spin the engine around and around but it just won't start. And when it does, it'll fire right as I let go of the key. Does this sound like a timing problem or fuel problem? The spark plugs are gapped at .040" The old ones I had were gapped at .050" with my MSD. Could this be a reason? I am just throwing out suggestions. Thanks for any help.
 

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Sounds like a text book case of vapor lock.
Try adding a heat insulating plemun spacer under your carb and if you don't have one already a hard fuel line that doesn't sit on the motor block from the fuel pump to the carb.

Vapor lock is basically the gas boiling out of the carb and/or fuel lines making it a hard start.
 

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Discussion Starter #3
I have a clear filter between the carb and pump and there is still fuel in it. could this still be the problem?
 

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Sounds like the ignition switch. When you go go start the car, the switch cuts the power to accessories, such as your radio, etc., then resumes power when you release the key. Sounds like yours may be cutting the juice to your coil when warm...
 

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It could be the coil itself. When the coil heats up, it won't function properly when starting and not put out enough juice until it cools down. Got another coil you can try?
 

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Discussion Starter #6
hmm well i have one at home but this one is almost brand new and it is mounted to the fender not the block. Does it matter if it is mounted sideways?
 

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The key here is that the motor sometimes catches right after you release the starter. Might want to check the voltage at your MSD, you could have high resistance in the path. When the starters cranking, the battery voltage is pulled low by the high amperage, taking the MSD below it's threshold voltage. Once you release the key, starter current drain stops and battery voltage goes up, bringing the MSD above it's threshold. The fact that this only occurs after the engine is warm makes sense because hot=higher resistance=lower voltage. Just a theory, but you could check the voltage at the MSD and compare what your geting to the MSD specs.

My second thought would be a malfunctioning choke.

Good luck!
 

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Discussion Starter #9
Also when it is not completely hot, it will start lazy. It'll start when the key is still turning, but slowly then i give it a little gas and it will run normal. does that make sense?
 

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It could be your engine ground. A hot starter pulls more amps than a cold one. A bad or poor ground will reduce a hot starters ability to perform. Try adding or improving the engines ground and see how she does.

Good luck,
 

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Shouldn't matter if the coil is mounted sideways. It is best that it is mounted on the fender. I had a problem with a yellow top where I would get a miss and I kept messing with stuff. Finally, in the middle of a parade, it quite. Let it cool off and it started back up. The symptoms can be a little funky on a bad coil because as was stated, a hot starter takes more amps and in combination with the MSD it might need more. It's and easy test if you have one.
 

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try a phenolic spacer, my car had the same problems as you are describing, the spacer cured them .
 

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Just a minor point here...oil filled ignition coils should actually be mounted vertically so that the windings are submerged in oil for cooling purposes. While this probably has nothing to do with your problem it is something that isn't given much thought. Mounting the coil horizontally wouldn't necessarily cause an immediate failure, but could easily shorten the life of the coil.
 

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I had this problem and installed a carb spacer to prevent the fuel from perculating when the engine is hot. It helped a great deal.
 
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