I have 2007 Honda BF150 with 400 hours on it. It's on an aluminum 20' Duckworth. I bought it used, and have only put about 10 hours on it. I started out with a14-1/2" diameter 19 pitch prop. The motor would rev to 5,500RPM. The dealer thought it was too much prop, since the boat wasn'tloaded down. We put 17 pitch on it, same diameter. This is wherethings stopped making sense. With the 17 pitch prop, the motor would runup to 5,500 RPM just like with the 19 pitch. The motor didn't sound likeit was working very hard, just wouldn't rev up any more. Speed dropped about5 MPH. I put the 19 pitch back on it. I verified the throttle wasopening, no slop in the cables, they are new. The next time out Ihad a long run up river. After about 4 minutes at WOTthe RPM's slowly started to drop off. In about 5seconds the engine speed dropped from 5,500 to 4,900 then heldthere. The problem repeated itself all day. Next I replaced thealready new canister fuel filter that was in the boat, and replaced the filterin the vapor separator on the motor, and the high pressure filter. Drained thewater separator (their wasn't any water in it). Took the boat back out. Now it can’t even get to 5,000 RPM with thesame load, although it stopped dropping RPM. I’ve ran it with the gas capoff, which didn't change things. I pressure tested the fuel transfer pumpon the motor. It made 10 PSI at idle and 8 PSI at WOT. I have alsotried unhooking the coils one by one, which made it really sick. When the dealer ran a diagnostic check, there were 10 overheating codes. One of them, my fault. Not enough water when flushing the motor. Also, according the ECM, the engine has never recorded anytime at wide open throttle. Any suggestions would be greatly appreciated.