I have replaced nearly the entire exhaust system... I have a new waterlift (waterlock) muffler on order will throw that in as soon as it comes.

Jon's description of what he saw with the black soot and the way the engine just lost power is almost word for word what happened to me. I didn't have massive amounts of black soot, but indeed there was soot where soot did not exist before.

I ran my engine hard last weekend... Started and ran great. I will put in that new muffler before giving it a speed run sea trial. I hope for at least a 1/2 knot more while motoring. I only had about 5.2 knots while motoring in the past, but while sailing, could get it to 6.3 easily. (10 knots of breeze while on a beam reach and all canvas flying)