Vibration

[Redrod]

4100 sca 370 Cummins
Battling with vibration for some time. Bow rail vibrates
New engine mounts
New shafts fitted and faced to couplings
Props balanced
New cutlass bearings.
Engines aligned to shafts and stern tubes.
Couplings attached to engines after 48 hrs from launch.
Any suggestions?

[mmwjr]

I’m assuming the vibration only occurs while running and not in neutral; correct?

Did you verify the struts are bent? Is there a specific rpm the vibration starts and does it get any better with higher rpm?

[Redrod]

Yes only under way.
Starts about 1500 and pretty consistent through the rpm range.
Unfortunately they did not have anything to check the struts. Do you know of a McGiver way to do that. No fancy tools available like a laser.

[mmwjr]

Originally Posted by Redrod

Yes only under way.
Starts about 1500 and pretty consistent through the rpm range.
Unfortunately they did not have anything to check the struts. Do you know of a McGiver way to do that. No fancy tools available like a laser.

No I don’t. I’m new to inboards a few years ago.