changing the oil in the outdrive

Old 02-18-06, 11:38 AM
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changing the oil in the outdrive

I have a 1995 Merc bravo 3 outdrive. I can not find the drain plug on the bottom of the lower stern drive as the book shows( Seloc ). It does say that some models have a drain plug behind the propeller. How would I find out if I have one set up this way? Can I call Merc with the numbers off the drive? I have the drive on a stand so I can see all around it. If I have to pull the propellers, do i need any special tools? Once the oil is drained how do you get the new oil in, any special tools? Any easy way of getting it in?
Old 03-04-06, 06:49 AM
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Hello John. Welcome to the Boating, Sailing, PWC, GPS, & Navigation topic.

May not be a plug. Likely to be two cap screws. One up near the top of the drive and one down lower on the drive unit. Remove both. Allow gearbox oil to fully drain. Than push in the new gearbox oil into the bottom hole until it flows out of the top hole.

While the gearbox oil is flowing, install the top cap screw. Than remove the hose used to add the gearbox fluid and install the bottom cap screw. Job done. Additional help can be obtained at local boat repair shops and by having any generic service manual if the original cannot be obtained.

Check the "O" rings on those two cap screws too. Must be in good condition and not hard, distorted, flattened, brittle or damaged in any way or water will entire the lower end and cause severe internal damage, etc.

Look at the drained fluid. Must be only oil, not watery and not milky in color. Any of these will indicate water is getting into the drive unit. If so, the lower end must be inspected by a pro and repaired, if needed.

Special tools? YES! Several for most jobs required. Must have specialized tools to avoid damage to some parts. But not usually for gearbox oil changes that I am aware of. Prop pulling may require pullers. In some difficult cases even a torch may be required to heat and expand the prop hub from the splined shaft, etc. Only a job for a pro and best left to the pros, in my opinion.

The diy resident boat service & repair professionals will have additional helpful information, suggestions and advice. Check back on your question several times for additional replies.

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Regards, Good Luck & Safe Boating.
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