WOT RPM range for 25hp Mariner

[JMichael]

I have what I believe to be a 1984 Japan built Mariner 25hp. I believe the stainless prop that is on the motor is the wrong size and lugging my motor at WOT. But so far I have been unable to find the recommended RPM for WOT. Currently it runs at 4580 rpm and I suspect it should be something like 5000-5500, but I'm just not sure. The aftermarket Prop Tech Stainless prop that is on it measures 9.75", but I don't know what pitch it is.

 

[Weldorthemagnificent]

Be either Yamaha or Mercury is guess. Here is an rpm page.
https://www.kirschbaum.at/ki_prop/pdf/2015/RPM%20Chart.pdf


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[onthewater102]

5500-6000 for the 25hp is what I show in my FSM for the same motor. Not sure of what type of boat you're running it on, I would imagine you want either a 12p or a 13p for a flat bottom john style. 10.125" x 13p was what they came with from the factory.