Reply To: 1956 Johnson 3HP compression

[tibor]

Based on my experience working on the two old Naptune magnetos, it is worth checking that you do not have an accidental short to ground on the condenser or the coil primary. Since you are getting some sort of spark on the secondary, it is unlikely to have a short on the primary but it takes a minute to check.

You should read the 1.5 Ohm (which as far as I know is good) when the points are open and a short (0 Ohm) when the points are closed. The beeping short testing does not work because most multimeters will beep at anything less than 50 Ohm.

You could also unscrew the coil primary (and condenser) and the then the points should read disconnect or short as you turn the crank (Close to 8K Ohm on the secondary should also be good.)

If you have an inductance tester, you can check the coils on their laminate core, I was getting between 0.7 and 3 milliHenry on the primaries and 8-9 Henry on the secondaries.

Is your motor one where the coils can be moved closer to the magnets? It may be worth checking the gap between the laminate core and the magnets then.