How to bring WOT RPM up to spec.

[Buck Horn Deer Farm]

I am working out all the problems in this old 1977 24' Searay weekender that I picked up last year. I can only get 4200 RPM at WOT. It had a Mercruiser 228 but was replaced with a 260. It is a preAlpha out drive with a 16x16 prop. I would like to get 4600 RPM. Any suggestions?

 

[SparkieBoat]

Re: How to bring WOT RPM up to spec.

if your motor is in proper running condition, you could try a 15P prop, it may not get you quite to 4600 but it should be closer than you are now. do you know the expected HP from your motor?? also if you could post WOT speed and gear ratio it would help a lot.

 

[Donzi GT250]

Re: How to bring WOT RPM up to spec.

Does your drive have hydraulic trim?
If so try trimming out your drive a little bit at WOT.
If you don't trim the drive up a bit your loading the drive and engine more causing a lower WOT rpm.