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Guys, I am facing a mystery. My 62 m37 will start cold and run for 10-15 minutes just fine. Then it stalls out, acting like it is starving for fuel. But when I try to restart it, it won't go. Feels like it is flooded. Even if I spray some ether, she won't catch. Everything looks fine. Fuel pump working. Any ideas? It has happened several times in the past few weeks.

Coil ,as the coil warms up it quits working. Check for spark at the plug when it happens.

Spark, fuel, compression. I'd look to fuel delivery, or as DJ pointed to, spark. I'd bet it is a spark issue. You could have a bad coil, but also make sure the coil vent lines are in place and all the fittings in the carb inlet are there. Otherwise the coil could overheat. I ran my truck for a whole summer without the vent lines and never had a problem, but I am sure my coil suffered some abuse.

Thanks guys. Had not thought of the coil. That is a good lead. I will take a look and let you know if it worked!

Vapor lock may be a possibility in these temps too?

If ether won't make her fire ,I'd put my money on coil,or possibly condenser. I fought this problem on my M38 several years ago,ended up the coil. Seen some coils on ebay listed as NOS and a American made one for around 65.00 for what it is worth.

Changed the coil. She started right up after. But 5 minutes later she stalled out again. Checked for fuel and it is getting fuel to the filter. Any other ideas? I let it cool and she started up again after about 15 minutes. Then repeated stall. Help!!

The things I can think of are coil, condenser, vapor lock, float issues, fuel line contaminants. What would happen if the valve in the exhaust manifold was in the winter condition during a hot summer day?

Jeff,

Just a couple of thoughts...........when she quits after 5 minutes did you pull a plug and check for spark while cranking? If not, do so to eliminate the electrical side of the problem.
Same goes for fuel.....not sure where your filter is located, but next time she quits pull the air cleaner and check for fuel. And if you use the choke to start is it fully disengaged after it starts? Are you running the stock M37 fuel pump? If so, is the heat shield installed?

Also, when it stalls......does it start to sputter and slowly die..........or just be running fine and then instantly die?

regards,
bob

Possibly gas cap problems,I can't recall if the M37 is vented or not. Try loosening the gas cap next time and listen for a rush of air. Or loosen cap and see how long it will run.

Bob, thanks for the suggestions. Seems to have spark so not electrical. When she does she sputters once, like a skip and then shuts right down.

Tried the gas cap truck tonight, trying to run with it open, but it quit after about 5 minutes again. Vapor lock somehow? Clogged fuel line or vent line? Not sure where to go next.

When it stalls out next, could you pull a plug and check for spark then? Just to rule out lack of spark

Ok. Spent the whole day chasing this issue. Checked for spark. Definitely have spark at the plugs. Replaced the fuel filter. Drained the fuel tank completely and refilled with fresh premium fuel. Still stalling out after about 5 minutes. Looks like there is not much fuel in the filter? So, should I next replace the fuel pump or start replacing fuel line from the inline filter before the carb all the way back to the electric fuel pump near the tank? Or am I headed the wrong direction? This issue is driving me nuts.

Specifically, do you still have spark after the truck stalls out, or are you testing spark on a cold engine before you have problems? Are you driving the truck, or is it just idling for five minutes and then stalling?

Testing spark after the stall. Still have spark then.

Have not driven out of my yard because I am afraid of being stranded. So it is stall after idling and/or short drives around my 2 acres.