What is maximum RPM for 1999 ox66 250hp?

I'm trying to get an understand at what point the RPM limiter would engage on this engine. It runs great up to 5600 RPM at 3/4 throttle making around 38 MPH GPS but anything above that it dies off to around 5000 RPM.

Is it the rpm limiter engaging at 5600 RPM? Some have suggested the RPM limited engages at ~5700 RPM.

I'm aware that I'm probably under-propped because I'm using the prop from the 200 I had on the boat which was replaced by this current engine. It would turn 5000 RPM - maby 5100 RPM.

Steve

[boats.net]

The operating range is 4500-5500 rpm's the overrev activates at 6200 rpm's. The rev limiter shouldn't drop it 500 or 600 rpm's. May be an ignition problem or fuel pressure problem.

I wonder if the position of the throttle position switch relative to the engine RPM could be the cause? That logic in light of the fact that the throttle is at 3/4 open at 5600 RPM due to the low prop pitch.

[formula29]

I have the same problem on a 98 250, it will spin up to 5700 when cold it seems, when it goes into open loop it will run great up to about 5400 then it will back down to about 5000, I have had the motor since it was new and it always turned 5700, I have cleaned the entire fuel system, sent the injectors out to be cleaned and it still does this? also put in a new 02 sensor, any ideas?

[boats.net]

I have the same problem on a 98 250, it will spin up to 5700 when cold it seems, when it goes into open loop it will run great up to about 5400 then it will back down to about 5000, I have had the motor since it was new and it always turned 5700, I have cleaned the entire fuel system, sent the injectors out to be cleaned and it still does this? also put in a new 02 sensor, any ideas?

Knock sensor may detecting a knock. Have compression test run on engine, decarbon engine, make sure fuel is good.