The remote needle valve bracket is just a hair away from the back of the motor mount now. If I relocated the needle, I could move it back maybe 1/4" and would then have to redrill the cowl mounting holes. I also have a hole cut for needle valve adjustment. I'd want to replace the engine mount and cowl if I moved the engine.

Exchanging the stock muffler for a Bisson would probably have me buying a new cowl as mine is cut for the long stock muffler. I have a little concern about this mod as I've read reports of happy O.S. 1.60 owners running the stock muffler and Bisson users having to mess with pumps, plugging muffler outlets, etc. to get the engine running right.

I could do both mods and buy a new cowl. This would be at a cost of about $80 and I wouldn't know if it would fix the problem until I did it. The engine is pretty heavy though, and moving it back a quarter inch may have a significant effect on balance.

On an airplane this size, is 5 oz. of lead as big a deal as I think it is?

Good flying,
Bob Scott