'99 SN WOT Speed & RPM Question

Nice to have another Utahan here on CCF.

Your numbers seem low. Your GT-40 should be 300+ horsepower. Running at 2,800 feet of elevation will have some de-rating on engine horsepower due to a lower volumetric efficiency.

My set-up is very similar to yours: Ski Nautique Open bow, 351 High Output (not GT-40), and Acme 654 propeller. I'm in the SLC area and the lake where I ski is at 4,200 feet of elevation. At Utah Lake, my engine turns 4,800 RPMs at wide open throttle and the Perfect Pass shows 43 MPH. If I'm alone in the boat, I can turn 4,900 @ 44 MPH.

With your engine and lower elevation, you should be seeing numbers similar to mine -- if not better. Other GT-40 guys will chime in, but with the 654 prop, I would have expected 5,000 RPM (even at 2,800 feet). I believe that you should see 44 to 45 MPH with your configuration (assuming everything is running right).

Hey Gang,
I am wondering if my data seems normal,

1999 Ski Nautique. Pro Boss GT-40, fuel injected.
I had the engine rebuilt in early 2013 by some quality guys. Has 130 hours on it now. Fuel injectors, cap, rotor, throttle body also new at rebuild.

The lake where I ski is approximately 2800' above Sea Level near St. George, Utah (Quail Reservoir)
Acme 654 propeller.

I did a boat test the other day. I was the only person on board, very little gear, no back seat. or back seat backrest.
WOT yields 41 mph on my perfect pass GPS speedo AND on my iPhone GPS speedometer both. Max RPM at WOT is 4400. Lake was flat.

Engine to drive shaft alignment is correct within 0.003.
Driveshaft passes the .003 trueness test on both sides of the strut.
Propeller has about 300 hours on it. No knicks. If you take it off the boat and lay it flat, it does not rock when you press on any blade face up or face down.

Throttle cable has full travel from idle to butterfly. I took off flame arrestor and visually looked at the position of the butterfly when I moved the driver's throttle arm.

Thank you for reading and your input,
Dave