I'm having a vibration issue on my 1986 SeaRay 21 cuddy. 170 Mercruiser I/O with an Alpha 1 drive.
Vibration is in real narrow RPM range between 1800-2100 RPM's. Anything above or below that and she is smooth.
The things I know are good and have checked: engine mounts ( I replaced a worn front mount in the spring) engine alignment is on the money, had the prop reworked and balanced, O/D u-joints are in good shape and lubed. Engine mounting points are solid- no wood rot or loose bolts.
The vibration is felt in the seat of your pants, not in the wheel.
I am going to pull the prop and put a dial indicator on the prop shaft to see if it has a bend, which I dont think is likely.
The only other props I have around to try are beat to hell, so i have no way to swap and see if the prop rebuild was done correctly.
Just looking for some suggestions or ideas on what to look for. Is it possible the vibration can be coming from the drive internals (gears etc)????? Thanks everyone.
Vibration is in real narrow RPM range between 1800-2100 RPM's. Anything above or below that and she is smooth.
The things I know are good and have checked: engine mounts ( I replaced a worn front mount in the spring) engine alignment is on the money, had the prop reworked and balanced, O/D u-joints are in good shape and lubed. Engine mounting points are solid- no wood rot or loose bolts.
The vibration is felt in the seat of your pants, not in the wheel.
I am going to pull the prop and put a dial indicator on the prop shaft to see if it has a bend, which I dont think is likely.
The only other props I have around to try are beat to hell, so i have no way to swap and see if the prop rebuild was done correctly.
Just looking for some suggestions or ideas on what to look for. Is it possible the vibration can be coming from the drive internals (gears etc)????? Thanks everyone.