2020 Yamaha F300 prop thrust bearing

[Tippetknot]

I just replaced the trust bearing washer on my engine. 166 total hours. For some reason the plating is galling off the base metal. Thoughts?

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[cliffm]

this is "best guess", I'd assume a higher than normal amount of abrasives? operation in a very "stirred up" silty environment?

I'd contact your closest Yamaha authorized service rep, and query the cause of this?

Maybe its an improperly finished part that needs to be covered by warranty? or maybe there is no impact other than visual?

 

[trailertrawlerkismet]

I’d like to find out the answer or solution. As a maintenance item I was instructed to flush the engine out with fresh water when returning to dock from being in salt water. If you are doing this then I’m guessing you can rule out salt erosion as a possibility.

Jim F

 

[Tippetknot]

Thanks Jim and Cliff

Yes, salt water operation. I always lift the prop out of the water when not running, and I rinse out the motor using the water rinse port. ( Not sure this matters for this bearing though, since it sits just behind the prop, external to any rinsing that is going on). The bearing turns with the prop, so I’m not sure where the galling is coming from. Maybe this is just a case of bad electroplating?


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[knotflying]

The shaft, washer and prop should all be turning together. Have you regularly tightened the prop at your periodic maintenance? The only other thing I can think of would be a slipped hub. Usually a spun hub would reduce RPM significantly and you would only be able to limp home at low RPM. However it could be very minor and caused your issue.

 

[Tippetknot]

Knotflying, great suggestions. Thank you


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[BB marine]

The area of most concern is the mating surface of the thrust washer and the prop shaft taper. Most of the time this area is damaged because of improper torquing and lack of anticorrosion grease. Torque is 40 LBS to the nut holding the prop. The area that you are seeing may be corrosion of 304 stainless do to dissimilar metals used Aluminum and the prop stainless steel alloy. There is still a lot of material left to the washer in the picture and could be reused I have seen a lot worse. I recommend a yearly removal of the prop to clean and grease the prop shaft splines and inspect all prop hardware. I have seen many times, owners neglect doing this and when they do want to pull the prop it is bonded to the prop shaft requiring extensive labor to remove it.