1991 60hp Johnson Bogs down

[renvette]

I have a 91 60hp Johnson 3 cylinder that bogs down on the water. It will get up to about 20 mph and shakes violently if I try to push it further. It runs great when out of the water with portable water tank. It appears to have trouble pushing the boat. Compression on all 3 cylinders was between 89-92. Any help or ideas are greatly appreciated.