I have one on a 4*60 too and it's a great engine. Tons of power! About the only thing that's wrong with this engine is the rear needle valve (air leaks). That can be fixed real easy. Use a 160fx rear needle bracket and a needle valve ass'y from an old .40fp. About $15 bucks total. Makes it run like a top!
I e-mailed OS about it and that's what they told me to do, and I haven't had a problem since I made the repair. I know.... OS should have done this for us, but.... anything that's man made can have problems, and what's life without problems.... Death.... I'll take the problems anytime!!!
Suptter