Ed Creggr,

Thanks for your comments about my OPS 60. I am running a Max Daily Handcrafted 11 x 7 1/2 wood prop on the OPS. They are actually the same props I ran on the engine back in the 70's. I really don't think a smaller prop is the correct answer. I may have to try a smaller prop if some of the other things I try don't help the uplines.
I really think I have a fuel tank problem or an air leak in the engine (gasket or bearing). I will probably try a smaller prop before I tear the engine apart. That would be the easiest fix for sure.
Ralph White