Vibration in reverse gear

[Cabtrack]

I have a vibration in reverse gear. In neutral forward and reverse increasing revs, no vibration. No vibration in forward gear. Any thoughts. Time motor is a Volvo MD2020 and a 130s sail drive with 3 blade folding prop.

[PEA-JAY]

Did this just happen suddenly?
Have you just done some work on the sail drive and this vibration started?
Have you hit something or caught a rope?

[Yngmar]

The most likely culprit is the folding propeller. Hop in the water and check for fouling growth and stuck debris.

[Cabtrack]

Hi Pea-Jay I recently changed out the rubber diaphragms on the sail drive.

[PEA-JAY]

If this problem happened soon after the diaphragm job make sure you reassembled the bearing housing in the drive unit using 8 x 25 bolts VP ref 946541 and not slightly longer ones

If you inadvertently used longer ones they will bottom in the threaded holes and you will think that they are fully tightened. On engaging reverse the bearing housing will move away from the lower unit and you'll have play on the shaft.

Have you found any oil contamination from sea water ingress?
 

[Cabtrack]

I used all the bolts that came out, no new ones and the oil is perfect.

[elias]

Had same issue

Check post
Vibration while reversing - Volvo saidrive 120 - engine penta 55

[Cabtrack]

Hi Elias
          Thanks for the information and will just monitor the situation. You haven’t had any issues since?