Possible damage to U-joint.

[ShayneA]

Hello, We had an issue last weekend were I had to put the boat in reverse with the drive about 3/4 up. This is an alpha 1 drive. After that everything seemed ok but later in the day I started noticing a vibration in the 2500 to 3500 rpm range. I was concerned that I may have damaged something so I pulled the drive to do an inspection. If you notice in the attached picture there is a wear groove on the u-joint where it contacted the housing.

The u-joint appears fine otherwise... smooth movement no play ect. Do you think it could be faulty? What else should I check?

Thanks.

 

[CharlieB]

Re: Possible damage to U-joint.

Hyper-extension of the u-joint during running or cranking can/will shorten the service life radically, depending upon the severity of the abuse.

The 'witness mark' clearly indicated abuse, what remains is to determine the severity. If your inspection of the u-joints indicates that the joints are still 'serviceable' then extend your inspection to other possible causes for the vibration as you could have a separate problem developing. Check the gimbal bearing, check the prop for a ding, you could have one cylinder misfiring and causing a vibration.

 

[ShayneA]

Re: Possible damage to U-joint.

Thanks for the response. I have also checked the gimbal and it appears fine. If the u-joint was damaged then I should hear something when turning to the extremes correct? I will reassemble and continue to monitor.