Lew,
I have a similar story about money in a Cub. I was cleaning and re-wiring my 124 this summer. It was pretty rough, needed a good cleaning. got it all wired up, cleaned the carb, etc. Turned it over and got it chuffing a little. I heard a BANG against the shed wall. Didn't think anything of it. Turned it over again and it fired, and two more loud bangs against the wall. I walk over to the end of the building (a good 10 feet from the tractor) and it turns out it was a nickel and two pennies that flew out of the muffler....
