1989 force 85hp not getting any speed

[Joshls1]

I have a 1989 bayliner 17ft Capri with a force 85hp on it. It was running fine then just lost speed. Before I could get it up to 28 mph but now it won’t go over 8 mph. Engine sounds and appears to be running the same though. I had an extra lower unit and prop available so I switched it out and still same issue. Figured I could at least eliminate that part as the problem. Anyone heard of this issue before????

 

[Jerryjerry05]

Do a compression and spark test.

 

[racerone]

Stop running the motor and find the issue.----If it is a plugged carburetor you could be starving one cylinder of fuel and OIL.----Could be expensive if you keep running it.----Could be water in the fuel.----Could be a ruptured fuel pump diaphragm.----Trouble shooting must be done.