2000 Mercury 50 hp 2 stroke lower unit oil seal replacement

[dt4ever]

I'm in the process of replacing the drive shaft upper oil seal in the lower unit from a 2000 Mercury 50 hp 2 stroke engine. I have removed the water pump housing assembly and gasket. My next problem is how do you remove the pump base to replace all the seals? Any input is greatly appreciated.

 

[Texasmark]

I passed over this yesterday as I didn't see what I expected to see. Since nobody else hit it I will try to help. Take another picture and this time shoot the bottom of the water pump housing aka showing what mates to what we see here. There are 2 seals down there somewhere, back to back (one keeps the LU oil in the lu and the other keeps the water out of the lu, just like on the prop shaft inboard of the propeller.

I just went out to the shop and looked at an old wp housing I had from my 90 hp. The bottom of the housing has a perimeter Oring to seal it to the mid section and the two shaft seals are in the bottom of it. All that's left would be the upper bearing which is what you are looking at if your seals are in the bottom of your water pump housing.

While waiting, the sleeve around the shaft: can you get a screwdriver under the edge (carefully) and prise up on it?

I just expanded your picture and it looks like the outer seal. Take a small screwdriver and push down on the part surrounding the shaft. If it gives, it is and beneath it is another inserted the opposite direction. Otherwise the bottom of your water pump housing will contain the seals, but from what I can tell, I doubt it on your engine.

Mark

 

[racerone]

I think the part with the seals in it is threaded.---May require a special tool for removal.

 

[dt4ever]

I passed over this yesterday as I didn't see what I expected to see. Since nobody else hit it I will try to help. Take another picture and this time shoot the bottom of the water pump housing aka showing what mates to what we see here. There are 2 seals down there somewhere, back to back (one keeps the LU oil in the lu and the other keeps the water out of the lu, just like on the prop shaft inboard of the propeller.

I just went out to the shop and looked at an old wp housing I had from my 90 hp. The bottom of the housing has a perimeter Oring to seal it to the mid section and the two shaft seals are in the bottom of it. All that's left would be the upper bearing which is what you are looking at if your seals are in the bottom of your water pump housing.

While waiting, the sleeve around the shaft: can you get a screwdriver under the edge (carefully) and prise up on it?

I just expanded your picture and it looks like the outer seal. Take a small screwdriver and push down on the part surrounding the shaft. If it gives, it is and beneath it is another inserted the opposite direction. Otherwise the bottom of your water pump housing will contain the seals, but from what I can tell, I doubt it on your engine.

Mark

I should've been more specific, my bad. The one in red circle is actually called water pump base (#22 part# 821307A2 according to Mercury catalog). It contains 2 oil seals and is hold by an O ring. I've tried prying it with flat head screw driver with no success. It might take more aggressive approach to remove it. Amazon has the replacement one for $41 if I decide to destroy it in the process.

 

[Texasmark]

It doesn't prise off as I suggested, it unscrews. That's the purpose of the slots I would assume, and the slots are why I said it unscrews. It may not come off easily and CCW is usually how you remove things if you forget or get confused because it doesn't want to turn. Since the shaft in in your way you will either have to fabricate a tool to fit the slots or forgo the slots and get on it with a pair of vise grips. Probably should do the best you can to spray a high quality, not
WD 40, penetrating oil around the threads to help in getting it moving.

​I can't see any slots in your pic. I blew up the parts breakdown and the picture of the seal installation doesn't lead me to believe that the seals are under this cap. But I have no idea. Knowing what the numbers represent in the parts might help. However, pay particular attention to the way the seals are installed around the drive shaft in the illustration. Pay particular attention to what I said about being back to back to seal from both directions.

Mark