Peter, Andrew and David gave it another try today. Andrew used bigger bolts and some other things to hold the snowmobile engine onto the go cart frame. I was hanging clothes outside at the time, and it was quite a bit of noise! But, they got it going.
Peter, taking the go cart for another spin.
Unfortunately, by the time Andrew returned from his route they noticed a bolt had gotten loose and is now missing, and the engine was bouncing around again. So, it's back to the drawing board.
Jim has been coaching the boys, but they are responsible to figure out what to do next. Good homeschooling project for a warm, sunny day.