C model mag problems

First thing to do is to set the points correct and try it.

Make sure plug wires are solid copper, and not resistor type, also plugs. 12V makes no difference, mag is generating its own spark(when operating). re mag, points, condenser and coil. The older coils when heated can short out, then be ok when cold.

Right Steve, So many people rebuild a mag and don't have it remagnetized.

I just spent over two hours last Saturday on a magneto. I changed points and condenser several times as well as trying three different magneto bases. Could not get spark at the points in a vise. I have the points that were new from a magneto that have lost the magnetic pull. I had other points that looked like new that came from used magnetos. I finally broke down and opened a sealed set of points and I had spark. After I installed them of course. Placing the magneto back on the tractor in time has become a problem with my crippled up hands and elbows. I found a new way for old crippled up old men, girls and boys. In the vice I checked the spark with the magneto re assembled with wires. After checking each terminal several times I stopped after I had spark on the number four terminal. I then placed a strip of masking tape over the impulse drive so it could not turn backwards and be ready to fire number four terminal instead of number one being next. This is the way I have always done this though. Trying to crank and check for air from number one plug hole and finding things didn't bend sharp enough to feel the air until I was past the point I could get the drive to match the lugs several times I then placed my thumb over plug hole number three. (the last to fire before number one) After feeling air pressure I then watched the drive as I turned the crank to see it past the firing point for number three and then kept turning the crank until the lugs would enter the drive. That put me in time.  If you are in time before removing the magneto a little pencil mark on the magneto and where if mounts will make sure it is in proper running time.

Wow, thanks!!

One more question.... The main shaft in the mag, with the gear on it that drives the points. Should this shaft be slipping? We noticed last night, that every 3/4 of a turn, it slips and does not rotate with the crankshaft when we roll the engine over by handcrank.

Without the impulse you typically would not have enough rotor speed during cranking to create primary winding current flow.

Edited by wkpoor - 28 Jun 2011 at 12:36pm