too many rpm's on gt-40

[barefoot111]

just got the boat running right from a fuel problem. I am an inspiring barefooter. I have always ran somebody elses boat until this weekend when we foot. My question is... am I turning too many rpm's? At 4000 rpm I am running 33 mph. Is this too slow for the rpm? I have ski'd and wakeboarded this boat since I bought it. Now I have to run 39-40 to barefoot and it seems like it turns alot. This motor does have a rev limiter I would assume since it is computer controlled. It is a 97 ski nautique. also for the first time ever I noticed a little tranny fluid in the bilge. Can rpm do this? It has a johnson legend 4 blade 13 x 16 prop. on this same trip my alternator started overcharging and smelled hot. I guess the regulator is going out. I cut it off and started it back up and it surged up to almost 15 volts then went back to normal long enough to get back to the ramp. I am going to take it to get checked out. I was in the water when all this went down. We only ran barefoot speed for about 4 passes lasting less than 40 seconds each. The last thing I want is to hurt my baby, please help. is the alternator just coincidence or did rpm kill it?

[DanielC]

I believe the RPM hurting the alternator is just coincidence. Make sure your battery terminals are clean. The battery might also be a little weak, allowing the voltage to surge. You also need to get an accurate voltmeter to check the battery voltage. If your battery is discharged, it will work the alternator a little bit, and it will run hot.

Check the fluid level with the transmission hot. With the boat floating, and level, and the engine idling, put the boat in forward gear, neutral, reverse gear, and back to neutral. Carefully check the transmission fluid level, staying away from rotating things. Take off your necktie before doing this.

I also have a 1997 Ski Nautique with 2132 hours on it. It will run about 46 mph, 5000 RPM.
Continuous cruise RPM 4000 to 4200.
Maximum (intermittent) RPM 4800.
I have two different propellers I commonly use, the OJ prop like you have, and the ACME 422. My boat runs slightly higher RPM, and a little stronger with the OJ prop, than with the ACME. The rev limiter cuts in about 5100 to 5200 RPM.
You can have a propeller shop add a little more cup to the propeller trailing edges to bring the RPM down, or sometimes the prop shop can add a little more pitch to your propeller. More pitch will slow the engine RPM down, but the boat may not run as fast, if you add too much pitch.

Your boat came with the adjustable Airguide Speedos. You can pretty much set the speedo to any wrong speed you want. Borrow or get a handheld GPS unit to check the speedometer accuracy.

[nms1991]

Also are you sure your tachometer is accurate? the rev-limiter is set for 5250 in the ecm for the engine.