Upper shaft oring

[DWABoat]

I just changed the lower unit water pump on my Alpha One Gen One.

How important is is the oring on the top of the shaft? I have heard different opinions.

some have said it was later deemed unnecessary by Merc.

Any mechanics know of a TSB about that?

 

[achris]

Not only unnecessary, but actually allows water into the splines. On ALL drives I service, that 'O' ring is removed and never put back! And yes, Merc later (and on replacement lower drive shafts) didn't even machine an 'O' ring groove.

 

[DWABoat]

Thank you for the response. I had heard unnecessary, never detrimental.

Well...I re-assembled right before I posted this and installed the o-ring when I did.

After I finished is when I started thinking about the o-ring from distant memory. (Over 50 memory)

Should I drop it and remove it or leave until next year and just don't put it on next time?

 

[DWABoat]

Addendum to my recent question: I put a lot of Mobil 1 synthetic grease on the splines right before I re-installed the lower. If the only risk is water to that joint, I would think the excessive grease would keep it out for at least a few months?

I would prefer not to drop that lower again right now but will if I must.

 

[Bondo]

Ayuh,.... Welcome Aboard,.... Don't worry 'bout it,....

Go Boatin',..... be Happy,.....

 

[achris]

Some times the o ring hooks up on the seal as it enters the spline. This is what allows the water in. Personally, I'd pull it out again. Throw the o ring as far as you can.