American Bosch Magneto Problem

[speronto]

Greetings,

I have a 1937 Cletrac AG with 4 banger Hercules engine.  The old American Bosch magneto needed replacing so I bought a rebuilt one from a shop back East.  When I test it in a vice mount, all four post put out enough spark to really feel it(yup, found out the hard way!).  I then mount it onto the engine and turn the crank but there is little, if any spark.  I am using the same wire core spark plug wires during both tests and the mount to the motor is bare wire brushed metal.  Nothing is touching the magneto.  Does anyone have an idea of what is going on here?

Thanks,
           Scott

[Blake Malkamaki]

Is it turning the proper direction? If turned backwards the impulse will not work.

Blake

[R Fink]

Did you have all the posts grounded when you were checking the spark. IF not you could have shorted the mag. Now i am not a mag. person but that is what i was told. Never turn a mag unless it can discharge the spark to plugs or ground.

[speronto]

Greetings,

Yup, the magneto turns left as required for an ooc engine.  I also can take the mag off at any time and return it to the bench and get spark out of it - so I dought that is the problem.  I am no electrical genius, but I am thinking that something was not included in the rebuild or some wire was not connected.  Thus the contact with the engine block diminishes/cancels the spark.  I guess there is nothing left to do but turn it in and get a Wico mag that works.

Thanks for your ideas and thank you blake, for the site, I check it out every day!

[Blake Malkamaki]

Don't get a Wico mag! Compared to your mag, those things are junk.

Just get yours looked at and get it working. There can't be too much wrong.

[R Fink]

If you have a good spark on bench and none on motor. I would set it on mount put in one bolt and try. It is possible i guess that some thing is makeing a short. I would say stop and think if you have at know how to mount and time you can figure this out. Just takes some thought. Good luck;)