I have a 24hp Honda beavertail longtail. My RPMs at full throttle are 4000 but in the water at full throttle are only at around 3000. I was expecting more like 3600 or 3700. What could be the problem? The hull of my boat is hooked pretty bad and I can’t really get up on plane, I don’t know if this is because of the hull or because of the RPMs not being high enough when the prop is in the water. Thanks for any help.

could be a numder of things... the depth that your prop is at when at full speed could be some of the issue. at full speed you want your prop right under the surface of the water. if its tracking to deep your RPMs decrease. Its like a trim on a speed boat... You may have to do some bending on the cav plate.My MD has a trim tab on top of the cav plate that can be bent.. check around on here. lots of good info on here. just got to dig around and find it... Check and make sure you got the right length motor for your tansom.... Maybe this will help you out... But you could have other issues going on...

Just thinking outloud here, but it could be that your prop is to big for your motor.. or your carrying to heavy of a load for your motor to handle and thats why its bogging down so much under load. try running it without as much weight in it if possible and see if that makes a difference. has it been doing this the entire time you've owned it or is this something new?

Well, the prop on it measure 7.5 inches across and I believe this motor comes with a 9" from the factory, that's how much the prop is worn down. It i the right motor/transom combination, and I don't think I need to bend the cavitation plate because when I throttle up the prop finds its sweet spot and is right under the surface of the water. Like I said 4000 RPM out of water, only 3000 in the water.

I really think it's the hull of the boat that is slowing me down. I bought this setup back in April from a guy I know and really just bought it for the motor because the boat was so beat up. I didn't think it would be this slow though.

I guess I will just have to wait til the end of the season and see if someone will let me put my motor on their boat and see what happens.