After looking more closely at the specs on my Comet 94C, the stock engagement appears to be at 2100 RPM, which is a bit high for the Kohler. I imagine that the 2100 is full engagement, right? I'd like engagement to start at about 17-1800. I don't think that should be the ultimate problem, though.

Does the 1190 clutch have a 1 1/8" ID? I'd give it a shot to try it out. When I rev the engine ever-so-slightly with the belt off, the clutch engages and disengages just fine at low RPM. Heck, it's brand new; it should work great. I'm conditioned to knowing how high-strung two stroke clutches engage, so I'm not sure how to fix this problem. My issue has always been with drive clutches, but I think I figured out those problems long ago...

On a side note, I think I found a muffler that may work for the customer. I have one off of an Attex that is essentially the same, and has a 90 on it. I'll also check with the other one as discussed, and should be able to stop by on Monday afternoon with one or both of them. If I could give that clutch a shot (as long as it's 1 1/8" ID), I'd appreciate the chance to try it out...