TJDILL

This is the third year that I have had a leak from the cap on the top of the sterndrive. I have watched my mechanic replace all three o rings and pressure test the unit and then the next spring I am leaking again.

The drive is winterized by my mechanic and he has told me that he has never seen water in the lube when he changes it at the end of the season. Any thoughts on what could be causing this to happen every year? Aside from replacing the three o-rings is there something else we should be doing? Is there a ball valve under that cap too?

Any help is appreciated.

TJDILL

4bus

iTrader: (4)

Are you talking about the top cap (which has a bearing) or the rear cap (which has a ball detent) ?

If it is the top cap (the cap on top of the drive with 6 bolts) it is most likely tweaked, and would only leak under load which pushes up on the cap for standard rotation. Try a billet top cap upgrade, and it will most likely stop. The oil level is well below the top cap at stand still.

If it the rear cap ( 3 nuts on studs, half of seal is below oil level), check the mating surfaces for paint erroison. The uneven surfaces can cause leaks even with new orings. Hit with a wheel and repaint surfaces. Lube shift detent and spring, reinstall

TJDILL

I believe it is coming from the topm cap (6 bolts) and that is what my mechanic has replaced the o rings under. At the end of each season the sterndrive is pulled and is winterized including drain and refill gear oil by my mechanic. The boat has not been run since the lube was changed. The outdrive was left up over the winter and when I lowered it I noticed the leak.

What does a billet cap do?

US1 Fountain

iTrader: (1)

Sure it's not oil that was sitting on the drive below the top vent screw when the lube was changed, and then ran down the drive when lowered?

Mr Gadgets

Pressure test it again, see if it leaks now?

Boat Tech

Is it item #'s 7, 8 & 9 leaking?

http://www.mercruiserparts.com/Show_...%28STANDARD%29

Starting with drive serial number 0W258350, Merc went from using an O-ring on the shift shaft bore area (# 7) to a new Seal/Plug called shift cavity seal/plug Merc part #19-865866 while the original O-ring used to seal passage is part # (25-62705).

Maybe you'll need to plug it after a thorough inspection of the two surfaces.

Good luck with it.

TJDILL

It is definitely coming from under the cap. I have cleaned it with a rag multiple times. I believe the small o ring has been bad the last two years. I have read some things about the cap being a weak point on the Bravo drives, but I am only running a 300hp motor, and most of what I read was related to much higher horsepower motors putting pressure on the drive housing.

Any thoughts on a billet cap, and any recommendations on brands and where to buy?

On a another note, I would have to go Ginger!

TJDILL

Boat tech, I believe that number 7, 8 & 9 is where i have been having the issue. My serial number is OM3000's, so I wonder if the plug would work? I just bought the o ring last week from a Mercruiser shop, so it does not seem like Mercruiser is recommending the plug for the older models?

Clustergear

The new style plug will work in older drive. I have seen many caps that somewhere along there life someone use a vise to hold cap while replacing the bearing or sleeve and the vise made small marks in cap where o ring seals, that new style plug usually solves the leak. Also look at both o ring cavities to make sure there is no marks that pinch o ring. I like to use 101 grease on o rings and bolts not perfect seal. Pop the cap and take a look. It's a easy job just take your time. Good luck and let us know what you find.

scarab600

I have had this problem the o ring slips out just put at little marine silicon on the o ring to keep it in place