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john deere mag timing

Dick Welty

I'm no expert on JD engines but I did adjust the low tension mag on one of my Associated engines many years ago. As I remember you turn the mag in a certain direction untill you can push in a pin into an engagement hole in the mag shaft. This gets the mag into a position where the coil is in a position to maxamize the amount of current that it will generate when the points on the igniter open.

The instructions will probably be to get the mag into this position then get the timming gears set up to the proper position then you will engage the magnito gear.

Then when you turn the engine over to start it the mag coil will be generating the maximum current just as the points are opening.

This is necessary because these magnitos are either AC generators or pulsating DC generators. The AC generators produce a sine wave current going from + to 0 to - to 0 to + and so on. The pulsating generators go from + to 0 to + to 0 and so on.

The function of timming the mag is the same for either type of mag and that is to get the timming to where the current is the maximum either above or below the 0 current point. Polarity is not an issue with an igniter.

Sorry I can't e-mail you this responce right now.

Hope this answers some of your questions.


John Hopkins

well here is the lay of the land
the john deere type e will run great on a low tension coil
starts on one turn
the magneto puts out about 2.5 to 3 volts. the magnet was just recharged
there are no marks on the gears to time them except a dot stamped in the magneto gear.
since the engine runs so well i want to leave the ignitor timing alone.
there must be clear instructions some where to help. i just can not find them.

Kris Eckhoff

Jonh hold the button in you will feel in drop into the hole if you have it timed right the ignitor will trip just as the button is starting to gome bake out of the hole good luck. :D KRIS

Rob Leonard

Last Subscription Date
Hi John, If I remember right all 3 gears on mine had marks, crank cam & mag. Your crank & cam timing must be set right if it runs on a coil so turn the flywheels over until the ignitor snaps on the compresson stroke and stop, then take your mag and turn it the same way it turns on the engine, (I think it turns to the right but I am not sure) and hold the pin in (right pin if it turns to the right, left it it turns to the left) then when you feel the pin lock in a hole and I think there is 2 180 deg. apart, hold it there so it does not move and mesh it in with the other gear and it should be timed right. Worked for me. Good luck. Rob


Last Subscription Date
their is a usefull peace of lititure on the mags and ingniters it is called serviceing john deere mags and ignighters worth wile picking up john.


This is from some old John Deere literature:
To time magneto, mark on magneto gear must line up with mark on cam gear, at the same time mark on crankshaft gear lines up with another mark on cam gear. In case the gear markings become obliterated, the magneto can be timed as follows: First, make sure that igniter trip is properly timed, then press in the timing rivet marked L in the magneto end bearing while the flywheel is turned slowly in the direction it runs. The rivet should drop into the notch and start out just as the igniter trips. Never attach a battery and coil to engine withoug first disconnecting magneto wire.