Mercury 50 Prop Seal

[New Yankee]

Does anyone have any experience changing the prop oil seals? I've got a small leak at what appears to be the inner seal. There is a gear tooth looking retainer of sorts which appears to hold the assembly in - do you need a specific tool to remove it?

I don't mind paying to have it done but suspect the shops are backed up - if I end up there what should I expect as far as $$?

No water entering the lower unit - did note when I changed lube there was only a couple ounces in it - now I know why.....

[Gus]

What year 50 merc is it? I have a shop manual that covers some in the 1980 + - a few years range. I could scan the pages and email them to you if you think it would be of help.

Let me know. I'll be out of town this weekend but I could probalby get it done next week.

[New Yankee]

Gus - that would be GREAT - it's a 81 model -my e-mail is [email protected] - THANKS!!

Guess I could get by just adding an ounce or two every month but it's not to environmentally friendly and I'd still know it wasn't right.

[Gus]

Just so I get the right diagram, although I'm sure the lower units are all pretty similar, You have a 81 50hp Merc. Is that a 4 or 3 cylinder?

Gus

[New Yankee]

Four cylinder - thanks again!

If buy any chance you no longer use the manual, I'd be interested.

Bob

Can't spell w/o spell check - "by" but I'd buy

[This message has been edited by New Yankee (edited 04-30-2004).]

[Knotwood]

The Mercs I've worked on had a stainless retainer that had tabs you would bend over into one of those gear teeth to keep it from turning around. You've got to bend that in so it lets you spin the aluminum retainer. A piece of pipe with square tabs welded on to match the configuration was all we used, on the small motors only two tabs were required, but on the four cylinders, four tabs worked out the best. Sometimes the corrosion got pretty bad and we used a propane torch to slightly heat the outside of the gearcase, and there were times when we had to break out the aluminum retainer with a chisel. It takes a little effort to loosen them up, so take it easy to start with, we'd welded a handle on the pipe to give us a litle more leverage, about a foot on each side should suffice. Most of the time you could replace that carrier without pulling out the shaft, check the area where the seals ride to make sure it's smooth and not gonna ruin your new seals.

[New Yankee]

Thanks Knot.

I suspected a tool would be required to spin that retainer off - I wacked it a couple times w/a punch and suceeded in breaking a couple of those plastic ears off - mine only had two of those keeper ears/flaps bent up but suspect it's been in there for life...

Absent Mr Gus's manual (thanks again) I'm getting less confident. I could simply add the ounce or so a month but I'm too retentive.....

What do you think, 2 or 3 bills at a shop?

[Bob Clausen]

You're right about that plastic retainer requiring a special tool. However, even with the special tool, they sometimes lock in the threads and have to be broken out. I did my 40hp Merc, and sacrificed the old retainer by (carefully) breaking it with a chisel. I think it cost me about $4.50 to buy a new one. No special tools or pullers are required after that.

[Gus]

you have mail!

Let me know if you don't get all 29 images.

Gus

[Wavey Davey]

Before you go through the work of trying to replace the lower seal, make sure it's leaking. Fill your lower unit with gear lube and run the motor awhile. Then drain the lower unit and see if it's low or if you notice water. Oil appearing to be leaking from the prop area could be just oil from fuel, the exhaust comes out down there too.

[New Yankee]

Thanks Gus - got them!

Wavey, good point. When I first got the boat I changed the lube - only had a couple ounces in it and was black as tar. Ran it once and changed it again for good measure. Noticed the first drops soon after - thought it was exhaust/unburnt fuel at first inspection so didn't worry.

Second time wiping up a small spot of clear lube I pulled the prop (and removed a small birds nest of line..) - the lube was pooling up from what looks to be from the inner seal.

No h2O in the lube - - clean and dry so that's good. Spoke w/a shop and a $100 will about get it if I get lazy(er)

Figured the leak has been ongoing for a few years - which explains the low initial level.

However, your point is very well taken.

Thanks for the tips guys.