last time I had the Hydrodyne out, I couldn't get it to plane out but once. The rpms don't get high enough (about 1500-2000 less than what it should.) I just winterized it, but before I did, I tried getting it up to the right rpms on the trailer, but it just went to 4000 and then backfired and died out. I restarted it just fine. It just won't hold at higher rpms. The fuel pump, lines, and carb are all in good shape and I cleaned them before I got it winterized. What could the problem be? (I/O Volvo Penta 80 hp)
If it backfired,(through the carburetor) it is lean. Check your high speed jets and the associated passages. Clean is not always clean in the hidden places. There could also be a restriction in the float valve causing the chamber to go dry at high power. It could be a fuel delivery issue also, pump, lines etc. jim