Hi Rick,

Thanks for the input.

You will notice at the beginning of the thread, (there are pictures) I had experimented with putting baffels in the muffler body to increase back pressure, this worked well. However, in the end we found that if we fixed the fuel draw by drilling out the carb input nipple and brass insert (see previous picture in an earlier poast), that we could elliminate the baffles. Since then I have done several engines just by drilling out the carb fuel nipple and carb brass insert - all worked well after that.

Since the time when I had inserted the baffles, I was looking at some of my older K&B engines and I noticed the muffler pressure nipple is on the extension between the engine and the muffler I was wondering if this may be a better tap for muffler pressure?

I have never played with the GMS .40, so I'm not sure what would fix it. Please keep us up to date when you get the problem fixed.

Fly4Fun,

Wayne Miller