Re: O-Ring on drive shaft

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Posted by Ed Mc. ( on September 29, 2004 at 19:11:10:

In Reply to: O-Ring on drive shaft posted by Terry Blalock on September 29, 2004 at 17:05:44:

It goes in the groove at the top of the driveshaft, where the splines engage the crankshaft. It keeps water from getting into the crank splines and rusting them out, or siezing the driveshaft in the crank.

Sometimes the o-ring gets caught when the lower unit is being reinstalled, and is drug out of position, as was yours. Or, the o-ring was too large and wouldn't stay put. Get the correct factory replacement o-ring from OMC dlr or Sierra etc aftermarket parts.

When you reinstall it, smear some outboard spline grease (you should be able to get some from a Merc or OMC dlr) on the splines but don't leave any on top of the crankshaft (grease up there will cause a hydraulic lock when the driveshaft engages the crank, and is hard on the bearings in both ends).

As an alternative to spline grease, I've used Sta-Lube blue waterproof boat bearing grease and it's always done a good job.


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