I have no get up and go

I am a first time boat owner. I recently bought a used 1992 thompson carrara 2000 it has a mecruiser 4.3L with a mecruiser alpha 1 gen 2 outdrive. When the boat is out of the water and i have the muffs on the engine goes over 6000 rpm's at about half throttle with a little popping from the carb occasionally when i give it full throttle. When i put it in gear the props turn fine in forward and reverse. As soon as i get it in the water i push it full bore and the rpm's only hit about 3500 to 4000 max the bow stays lifted i cant plane out and i only go about 10 to 15 MPH and the engine sounds like its bogging onll when its in the water. I have changed the oil changed the spark plugs and wires and ialso pulled the lower unit and had the water pump changed out as well as the gear oil. Can someone please help me tofigure this out?

Re: I have no get up and go

When the boat is out of the water and i have the muffs on the engine goes over 6000 rpm's at about half throttle with a little popping from the carb occasionally when i give it full throttle.

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Thank you for playing the "Let's Destroy An Engine" game!!!!

Not a real good idea to free-rev any engine way past it's red-line ......

If it's really turning 4000 RPM (hard to understand how it sounds like it's "bogging" at 4000 RPM) in the water and only going 15 MPH then something's slipping, either the prop hub or the engine coupling. Put a couple of marks lined up with each other on your prop nut and the outside of the prop itself. Run the boat and see if they're still aligned when you come out of the water. If they are not, your prop needs to be re-hubbed. If they're still aligned the only other thing that can slip is the outdrive coupling. To check that, take the outdrive off and see what the splines on the outdrive input shaft and the splines in the coupling on the back of the motor look like.

Re: I have no get up and go

I'll check.

Re: I have no get up and go

Have you changed fuel filters and run fresh fuel?
4000 rpm and 15mph does not sound correct at all..
Popping out of the carb....sounds fuel related. Was the engine timing checked?

Re: I have no get up and go

Have you had a boat before. Sounds like you have it trimmed all the way in. If thats the case your plowing water. If your running a 21 pitch prop and doing that it'll have a hard time getting enough speed to plane.