57 will not reach wot rpm

"I have a 1998 Trophy with 5.7

"I have a 1998 Trophy with 5.7, 1.47 gears and a 14 1/2 x 17 prop and the best wot is 4000.
Bayliner's spec for prop is 15 x 17 and the mercrusier 5.7 WOT is 4400-4600.
Where should I start to look for proplem ?
Andy"

"Does it need a tuneup? Small

"Does it need a tuneup? Smaller prop diameter, 14.5", will lose 100-200 RPMs. Stainless steel will help a little. Is the foam and wood waterlogged? That is extra weight."

Also might check to be sure th

Also might check to be sure the throttle is opening all the way - might need cable adjustment. }

"What size Trophy? I've go

"What size Trophy? I've got a 1994 2352 W/ factory hardtop and 5.7 4 barrel alpha 1 gen II. Played around with props this year and went with a SS 15" pitch 3 blade. My wot is now where it should be, 4400. In smooth water I cruise at 3400 @ 24.5mph and wot is 33mph. I tried a 16x16 4 blade aluminum and it was great for docking and with no load but could not reach correct wot with any load at all."

"The engine was a rebuilt and

"The engine was a rebuilt and the dealer just dropped the old parts on the new block and started it up and said there you go...
The prop is ss and I will be getting the engine checked by a machanic this week. Thanks for you input. This boat is a 1998 and has been out of
service for a couple of years. Last year when I purchased it, the dealer had the engine rebuilt before I took possesion, at that time it seemed
over propped and it was running a 16 x 13 pitch and would only turn 3800. Replaces prop with 14 1/4 x 17 and no change. Unfortunately when
they set it up the knock sensor had a loose wire. I must have moved this wire once day and the boat worked as it should 4800 rpm at 42 mph.
Unfortunated the wire came loose and the rpms dropped. the end result was a blown head gasget and a cracked block. The rebuilder replaced the
engine and told the dealer it looked like a timing problem that caused the problem.
Anyway we are now on engine number 2 and will be checking the ignition and timing.
Thanks,
Andy"

"Should check and verify base

"Should check and verify base timing, and that
advance is working. That could rob a few hundred rpm. Is bottom of boat spotless? Also verify your throttle is actually 100% as cables could be a little out of adjustment.
Kurt"