Extra O-ring in water pump kit - what's it for?

[Hvymtl]

Ordered the basic Sierra water pump repair kit for my 97 90HP SPL. Have one extra o'ring in the kit I don't know where it goes.

So far I have used the impeller plate gasket, metal plate, o'ring for the impeller, impeller, o'ring between impeller housing and water pump housing, Big o'ring for water pump..I have one smaller o'ring left??????

 

[WernerF]

Re: Extra O-ring in water pump kit - what's it for?

O-Ring on the drive shaft's top end, below the splines?

 

[1946Zephyr]

Re: Extra O-ring in water pump kit - what's it for?

And that one is very important too, because it will prevent water from getting in your plines and seizing your drive shaft into your crank

 

[out 2 launch]

Re: Extra O-ring in water pump kit - what's it for?

Unless I'm mistaken the drive shaft sealing o-ring is contained in the crankcase head assy. and is not installed on the shaft.

 

[Watermann]

Re: Extra O-ring in water pump kit - what's it for?

Yeah it's for the grove in the drive shaft that goes below the splines. If you've put her back together already then and your pulling the lower unit every other year to do the water pump and not in brackish or salt water then I wouldn't worry about it.

 

[Hvymtl]

Re: Extra O-ring in water pump kit - what's it for?

Guys ..not following where that o'ring goes? On the shaft itself up by the splines - wasn't one there when it came apart and BRP doen't show on either? There is already a spring type seal at the pump end

The leftover o'ring is about the size of a quarter and will fit the groove just below the shaft splines if thatr is where it is supposed to go.

Do I need to pull the old one out if it is lodge up head assy?

 

[Watermann]

Re: Extra O-ring in water pump kit - what's it for?

I wouldn't even worry about it and that o ring wouldn't be able to get stuck in the driveshaft tunnel. Sometimes they just roll off the end of the shaft and fall on the ground without being noticed when you drop the lower unit down. The only function they have is to keep water from getting into the splines which could make it difficult to drop the lower the next time if it corroded. The first time I changed my impeller, ten years ago I didn't know that an o ring went there and it didn't make my driveshaft get froze in place let alone corrode, it's stainless steel. Just remember the next time you do the impeller change and put in on. Your good.

 

[the machinist]

Re: Extra O-ring in water pump kit - what's it for?

I have never seen these O-Rings installed inside the crankshaft spline, rather hard to do unless you pull the powerhead anyway. I know that OMC dropped the driveshafts with the groove cut for the O-rings on the later 9.9/15hp because this groove weakened the driveshaft allowing it to break off at that location.

If you simply grease those splines liberally with waterproof (trailer wheelbearing grease) that pretty well takes care of the potential rusting problem.