1939 M timing with Magneto

PaulGinMn · Jun 22, 2011

I am just finishing my 1939 M that had a distibitor. I am just getting it back togather after sitting for a couple of years. There are 2 notches in the pulley and I am assumeing the first is TDC. I set the mag impulse to click right at TDC or the first mark is this correct? I had it fire up for about 5 seconds and cant get it to fire again. Im not sure if it is timeing or if its something with my carb. Thanks Paul

Bob · Jun 22, 2011

I can never remember which mark is which, HOWEVER, it's EASY to figure out... remove the #1 sparkplug and insert a long plastic straw (or similar harmless thing)into the hole and bring the engine up on #1 an note at what point the straw rises the highest... that will be TDC.

Janicholson · Jun 22, 2011

It needs to be on the compression stroke. Put a thumb over the hole and crank until pressure is coming out of the hole. Stop and then use the straw. to assess TDC.
The mag impulse coupling must be cocked so that just as it gets to tdc, it fires. The mag must be in place, and retarded. Then the engine rotated to compression TDC, then the mag turned till it trips(click/spark) then tighten it down. Jim

PaulGinMn · Jun 22, 2011

Thanks Guys, I went out a rechecked the timeing and I think I have it right. So I pulled the carb apart and I had bad gas and alot of rust so I am going to soak the carb and rebuild it. This junk gas we have now is something else. Thanks Paul

1939 M timing with Magneto

PaulGinMn

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Bob

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Janicholson

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PaulGinMn

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