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Boat Repair/Mercruiser drive slips at speed


Daniel wrote at 2014-05-26 01:43:47
I also have a alpha one out drive. I was having problems with the prop seeming to slip.  Of course you start to think lower unit.  Most of the forums I have searched said exactly the same thing.  Must be a prop that's slipping on its hub.  Well I have checked that with no problem.  I also tried adjusting the cables and that didn't solve the problem, although I now know how to adjust the cables properly now.  So thinking the worst I dropped the lower unit only to find really nothing wrong with it either.  I have been a machinist for 30 years now so I am no newbie to mechanical workings.  Upon closer examination there is a cable that connects to a aluminum shift block that stays with the gimble after you take the outdrive off.  Now keep in mind it's not just the lower unit or as some people may refer to it as a foot, but also the part that attaches on the topside of the unit.  It takes 6 bolts to remove this piece and will only come off with dropping the trim cylinders and pulls straight out from the boat.  On the end of this block is a set screw that takes a 1/8 Allen wrench.  It is wire tied with a small piece of Twisted wire.  Cut the wire off and tighten the set screw taking the slack out off the shift cable and see if his saves you $2600.00 dollars!!!  Of course you will need a new gasket to re-seal the unit back to the gimble but it's better than purchasing another unit.  I did not purchase a new unit but this seams to have fixed the problem, best of luck in your money saving recreation items and hope this helps.

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Al Doyle


Repairs and troubleshooting marine engines and sterndrives. MerCruiser, OMC, and Volvo. Tuneups, maintenance, troubleshooting, sterndrive repairs, repowering, maintenance intervals, estimates, propeller info, etc. No help for outboards, sorry.


20 plus years experience in marine engine/sterndrive repair. Past factory certifications with MerCruiser, OMC, Volvo.

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