Hey guys, I'm struggling to get my car to run on magneto again. Background - car was pulled out of storage for 45 years, had coils rebuilt and started daily driving. One time I was able to switch to magneto and the engine kept running. I was able to drive about a mile then the engine started coughing and sputtering and finally just quit. I switched to battery, fired it up and kept going. I have been driving the car on battery (6v) for a few weeks now. I have to recharge every once in a while.
Things I have tried, realized or switched -
The ammeter was wired backwards.
Rewired the ignition switch so that the magneto side was now battery, to rule out the switch.
Did the lightbulb test, bulb glows bright at high throttle but didn't burn out.
Tried to recharge the magnets on the magneto.
Tried prying the crank forward.
Did the lightbulb test at the ignition switch to rule out the wire (it looked a little shady in spots)
I can't find a analog voltmeter to do the actual readings.
Any advice or other things to try?
Have you checked/cleaned the mag post? Sometimes lining fuzz collects there, gathers metal debris, and makes a partial ground. Be gentle. It's easy to strip the threads.
Yes, did that as well. There was fuzz but I don't think it was enough to do anything but I cleaned it off. Still won't run.
John< measure your mag voltage. that tells all.
Go to the electric supplies aisle at Lowes or other big box store and you will find small ANALOG type VOM (Volt/Ohm Meter). They sell for under $15 typically. I have a small one from there that I keep under my seat and won't care if it gets loaned out and never comes back which happens to me a lot. Look for one that has a 50V AC scale on it. Nice to also have a 10V or 15V DC scale on it to for other things. Then do the 1156 light bulb test again while running the engine on battery. I think you said you "tried" to recharge the magnets. There is no such thing as "try". Yoda said there is simply "DO" or "DO NOT" You need at least about 7V at idle but more importantly you need to be able to crack the throttle and quickly see the AC voltage go above 20V and the bulb get really bright and hopefully burn out. Then you have a magneto. DO NOT waste your money on even a cheap digital meter since it will give you erroneous readings when you run the test.