2005 225 V-Max HPDI low max rpm's

[allinejr]

I bought this motor new/used from the dealer in 2006. The motor was on a guide's boat, when the power head blew and was replaced. They gave him a new motor and I purchased the motor with a new boat (22ft CC Blue wave). Problem is that the max RPM's will not exceed 5200 rpm.s The original prop was a 4 blade 13 3/4 X 24 prop and the max ROM's was 5100 rpm's. The dealer recommended to change the prop so I went to a 14 X 19 prop 3 blade prop and the RPM's went up to 5200 rpm's. I have run a compression test and all cylinders are the same. I changed plugs with no difference. The only thing I noticed was the top plug on either side had a black coating after one fishing trip. Is there an adjustment for WOT or a rev limiter?

 

[Casco Bay Outrage]

Re: 2005 225 V-Max HPDI low max rpm's

It could be the prop is still to large (diameter and/or pitch), your engine is mounted too low or the throttle linkage is not adjusted so with the throttle lever at WOT, the linkage is not at the end stop.

Before you buy another prop, what is the mounting position of the motor on the transom? We want to know how many holes down from the top are the bolts. Additionally, where is the anti-cavitation plate in relation the the bottom of the hull. To get a good measurement, place a long ruler of straight stick on the top of the plate and see where it touches the hull. It should be at or slightly above the bottom.

If the engine is too low, raising it up will reduce drag and increase your RPM's by 150-200 for each hole you go. Do not raise it without getting feedback. An engine mounted too high will not perform well and possibly not get enough water and overheat.

Posting a photo will help.

If your engine is mounted correctly, check the linkage in the engine. Once that has been checked, tell us the gear ratio of the motor (in the manual) and one of the prop guru's can give you a recommendation if it is needed.