I was given a project by the son. EZGO Marathan ( I think ) with a 2-cycle engine. Starts, but misses badly in either direction. ( like it was only firing once every few revs. ) Up on blocks. Very mechanical person, but new to this type engine setup. Compression seems very good, turning over by hand. Carb is a Mikuni BV-24. Points are set at .015. Carb seems clean to me. I have looked thru many post, and this seems somewhat common ( but not to me ). Is a common problem with this engine to blow a crank seal ? ? Thanks for ANY help. John