RPM's too high, new to Nautique

[JT96SS]

Just bought a 1996 Super Sport Nautique, new to Nautiques and boat owner, had a vibration so I had the prop reworked because it was pretty beat up. Vibration is gone but my RPMs can go to 5500+ when I'm at WOT. It's a 14R18 prop, not sure what came stock on this boat. Owner's manual says 4800 max intermittent, 4000-4200 normal cruising. Thought maybe a different prop, asked Gary at Delta he suggested a 644 but said my RPMs will probably go higher. Then he said "I think either your tachometer is giving you an incorrect reading, your current propeller is not to factory specs, or you have a transmission problem."

Boat runs great, am I looking at WOT wrong, meaning is WOT at the hole shot only or from cruising speed? And will the RPMs go 5500+ with a GT40 Pro Boss from cruising speed?

Any thoughts or clarification on my confusion?

If this is normal, any suggestion on a better performing prop to Ski and wakeboard? Is Gary at Delta suggesting the right prop for my boat?

[s_kelley2000]

I would venture to guess that your tach is off or your prop is much lower pitch than 18. Either way I would think you would hit the rev limiter if you were truly turning that many revs assuming the GT40 has a rev limiter? How fast are you going at WOT? I'd throw a shop tach on there and verify your RPMs before digging too deeply into this. I believe 14x18 would have been the stock prop on your boat.

[JT96SS]

At WOT it'll get to 44-45mph with me and another on board.

So what your saying is I should never see the RPMs go over 5000-5100? I know the tach is going to 5500+ RPMs

Thanks for following up

[nms1991]

JT96SS the rev limiter o the Gt-40 is 5250 rpm so there is no way the engine is reving past that so you more than likely have a ba tach(common with teleflex gauges). but you can check with with a shop tach to cofirm.

[JT96SS]

Thanks guys, my next mission will be to find a shop tach or just buy a new tach, whichever is cheaper. Once I figure out where the RPMs are I'll be back to ask about props and what will work best for both ski and wake for this boat