225 hpdi rpm

[luigisbass]

I have a 2006 225 HPDI w/25 T1 prop on a 10" slidemaster manual jack plate on a 2006 Ranger Z20 and my rpms are low they are only 5450 at wot. I only weigh 165 and the boat is not loaded that heavy but when I'm with another person in the boat the rpms are around the same. The throttles are opening all the way I had it checked. I had rose the motor up to about 2 3/8" below pad from 3" and I gained 50 rpms. Does anybody know why my rpms are so low?

PS all filters and spark plugs were just changed.

[greasyshaft]

if you can put a test prop on the engine to see if it will rev out you can isolate it to a engine problem or a hull/prop issue. does the boat have a dirty bottom ??

[rodbolt17]

did it ever rev higher?
it may be slightly overpropped.

[luigisbass]

I just had the powerhead rebuilt in September but the rpms were the same as before the rebuilt exactly the same.

I will try a different prop when the ice melts to see if the rpms change.

The pad of my boat is pretty clean. Every Z20 w/225 has a 25P prop on it getting more rpms than I am. I never heard of anybody running a 24P or 23P on this boat and motor combo.

Has anybody else experienced this issue and know what the cause can be?

[rodbolt17]

only way to really look at it is a high speed run with YDS recording then analyze the data.
pay attention to fuel pressure,TPS,CPS and barometric pressure.