Re: hot engine hard starting

Posted by Tim Cole On 2016/7/11 15:01:14

All of this is great, but it's not isolating a system or a cylinder.

If there is fuel starvation then a few pumps of gasoline from a squirt oil should cause the motor to kick over.

If there is an ignition problem then an adjustable spark tester from NAPA should indicate that as would a plug reading. If the plugs are black velvet colored then ignition is probably weak. As well, I always made sure the timing was correct. Sometimes that meant expending effort to get good timing marks for use with a light. If the motor is turning over fast while cranking the connections are probably good.

Sometimes when those motors are old they are not producing enough compression and cranking the motor for an extended period causes the cold fuel to create enough seal to get the motor going. I had a high mileage Plymouth like that. It had good carburetion and electronic ignition, but when it was hot it had to crank and crank with the throttle wide open to start. So I would check compression when hot, and try a couple of squirts of Marvel oil into the cylinders when hot. If the motor kicks over then it is losing compression.