I have a craftsman riding lawnmower model 917.273646. It had no spark and I replaced the Magneto and it ran like a charm. I was cutting my lawn and shut it down to dump the grass. It won't start since there was no spark. I bought another Magneto and it starts. After finish cutting my lawn, I shut it down and then can't start it. No spark again. What may have killed the magneto again?

Phi

Hi,
Replace the key switch and the armature. The switch has an internal short feeding battery voltage to the armature whice blows it.
Peace,
Clarke