Boat has trouble gettingup on plane -1979 Glasply Volvo w/Volvo 140a

[john lyons]

My 1979 17' Glasply w/a 17 pitch prop will not get up on plane with 1 passenger unless we lean over the front of the boat.
The engine which is a 1979 Volvo 140a will rev to 3800 rpm then will not go any higher unless we lean over the front of the boat then it
will rev as high as 5100 rpm. The boat planes at 4100. The engine does not misfire at 3800 rpm it just will not rev any higher. I tried a smaller (the original prop) and it would not even rev to 3000 rpm. The engine has had a complete tune up. The boat mechanic says trim tabs will help.
Any thoughts?
Thanks,
John

[ezmobee]

Are you by chance lugging around a bunch of wet flotation foam?

[smokingcrater]

I'd say a compression test for the engine might be in order... Sounds like it is a little tired...

[john lyons]

I don't think so. The boat is stored inside. How doI check?
Thanks for the idea.
John

[john lyons]

That was one of my thoughts also.
Thanks for the input.
John