Hello I have recently acquired a new project. The motor (46 flathead) was rebuilt and was running, but aren't they all. I can get the motor to fire up, but it will not idle. If I keep the key turned and give it gas the motor will keep going. Once I take the key out of the starting position the motor dies out. I was thinking this could be a timing issue, but then I don't know how to set the timing on the Helmet style distributor. Is there anyone out there that has any thoughts? Or have you had the same problem? I could really use the help, thank you.
It's not a timing issue... Sorry if this sounds like a stupid question but..... Do you have an ignition with an actual "start" position...spring loaded that returns to "run" when you release it or do you have an on-off key switch with a starter button?? If its a switch with a start position...holding in that position should result in the starter remaining engaged. Is this the case? Regardless, it sounds like your problem is that when the starter is disengaged voltage is lost. Trouble shoot your ignition system and I think you'll find the problem.
No such thing as a stupid question. It's not a push button start, it actually has a start position that returns to run. I'll check the ignition system though.
I'm not convinced that it is ignition related. If it was a key issue it would not stay running if you gave it more gas as you state. I'd narrow it down to a fuel or an ignition problem by having a friend spray some gum cutter into the carb as it is dying to see if it stays running. If it runs a little longer then you have a carb problem. It could be something as simple as an idle mixture adjustment. Do some more diagnostics before you chase all those wild geese.
How is the coil wired? I bet you have a rewired ignition switch and if you look at it there is a wire from the 'start' position of the switch going to the coil. I also bet there isn't another wire from the 'run' position and when you releaes the ignition key you are loosing your hot wire to the coil. Need to rewire so that during start the coil is supplied by an auxillary terminal on the starter solenoid and it drops out when you release the key and the coil is then fed from the 'run' terminal of the starter. Just a thought to check.
I'm going to make a video of whats happening, that may help diagnose the problem as well. With all this technology these days, I might as well use it. Thank you to all so far who have helped out. I will try everything.
This is too fkng easy. Turn key on. Do not start. Measure volts on pos side of coil. If no volts get new resistor.
Good thing that I didn't post before I read the whole thread as those were my exact thoughts. Turn the key to "on" and check power at both sides of the ballast resistor to eliminate that. If there is no power to the ballast resistor start backtracking up the wire to the switch. Or it might be easier to go into the switch and work the other way. Key in on position and check for power at the ON or IGN post on the switch and work from there.
BUMMER. Sorry that it doesn't stay running. Try a jump wire from hot directly to coil, bypassing switch and the new resister (which my have gone bad). I only know that it did stay running after I initially did wiring. Ignition switch terminals are marked so easy to determine if correct. Also wires are different colors but same from one end to the other, easy to trace. Here are pics of engine when I removed head, pistons stamped 0.30.
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