Leaking seal in lower unit?

[Blue Gray in PA]

When I brought my Ally home from the river two weeks ago, I tipped the motor part way down as usual to drain the water out of the prop. A few days later, I noticed the water that ran out of the lower unit also contained gear lube - I could smell it as soon as I walked into the garage. I cleaned that up and lowered the motor all the way and it leaked some more water / gear lube out over the next two days. I removed the prop and the seal behind the bronze washer for the hub looks OK. The gear lube appears to be coming from the bottom of the lower unit and is present in the small trough at the bottom of the housing.

How many seals are there in the lower unit and how hard is it to open up? Does it require special tools? I have built numerous automotive engines and set up a few rear-ends for cars but nothing for boats. I have the service manual but haven't had a chance to dig it out yet. The motor is a 150 HP Mariner Mag 3 and any preliminary input would be appreciated before I take it to a dealer and wait for weeks to get it back.

 

[Stace]

Drain your gear lube and see if its milky. There is a large o-ring seal on the bearing carrier that may have cracked. It maybe coming out of shift shaft seal or water pump housing seal. Usually if oil is getting out water is getting in unless it was overfilled. :shock: You will need a gearcase cover nut tool (which is easy to build with pipe and 3/8" key stock) or you can buy one at www.precision.bz for $113 part #73688. Shift shaft bushing tool #31107 for 26.35 and no special tools for the water pump housing. Hope I've helped!! Stace

 

[Blue Gray in PA]

I put a new water pump unit (housing and all) in June of 2004 and planned to put another new one in in spring 2006. I change the gear lube each fall before I put it in storage and didn't have any problems until the other day so I doubt it got too full but anything is possible. I guess I'll pull the lower unit off and check the pump housing seal and the shift shaft seal at the same time. If they both look good, I may take the unit to the dealer and ask if they can open it and check and install the seal if it's bad. Thanks for the info and I'll let you know what I find.

 

[alli ss]

just have them do a vacuum and pressure test. they will see dolla signs if you tell em to just fix it :lol:

 

[JR]

GC service

I am a little of a finatic about my GC, but I have all the seals replaced, along with the waterpump every spring during the "Annual". My Sportmaster has over a thousand hours on it with just a propshaft replacement, after my small diameter shaft snapped off. It is a good time to grease the spline and clean off any corrosion too.
JR

 

[Blue Gray in PA]

I agree that the "just fix it" approach is not the route I want to take. This boat and motor sat for six years in a garage before I bought it and that's why I put in the water pump first thing. Replacing seals now would not be a bad idea since the motor is a 1992 model and the seals are original. I have run the boat a lot this year and it just now started leaking so I think the seal probably gave out during or at the end of my last fishing trip. The vacuum and pressure test sounds like a good idea to verify the leak area and to verify I don't have two problem areas instead of just one.

Does anyone have a drawing of how to make the wrench Stace mentioned that I would need to open the unit or is it just a simple spanner wrench made from bar stock and two keyways? I may still tackle some of this myself due to money being very tight right now but I don't want to crack anything either.

 

[BP]

http://www.outdriveshop.com/tools/98toola.pdf

Bearing carrier retainer wrench tool is #91-61069
I think they are about $70.00. I made my own from a MercedesBenz balancer tool.
Torque on the spanner nut is 250 ft lbs so whatever you make(if you go that route) it will have to be H.D.
Sometimes the bearing carrier doesn't just slide out after the nut is removed and may require heat and a slidehammer. There is also a tiny key that will come out with it, watch you don't lose it.
If you don't tighten the carrier nut enough after the repair, the carrier will spin in the case and will damage/ ruin it.

 

[Blue Gray in PA]

It sounds like I should leave it attached to the motor to make it easier to hold with 250 ft-lbs of torque required. Also sounds like I might be better to buy the tool to ensure it will withstand the torque required - I've broken enough wrenches in my day including a few specialty ones - it seems things get tighter with age and 13 years is a long time since this unit has been apart.

 

[BP]

Yes, good ideas.
Not to nag but clean the threads out real good before you spin the carrier nut off. It won't take much to gall the threads.

 

[Blue Gray in PA]

After a brief phone conversation with the mechanic at my local dealer, he said it "should" run around $125 to replace all the seals including labor and pressure testing. He can have it done by the end of next week so I decided to take it there since I will not be home much next week and our season is ending soon. He will call me if anything looks bad inside and would change the price. I did drain it and got a mixture of water and gear lube but most of it had already leaked out on the floor. There was very little debris on the magnetic drain screw and it was all powder - no solid pieces. I'm keeping my fingers crossed.

 

[BP]

Well for what it's worth you probably did the right thing.
I hope it turns out for the best.

 

[Blue Gray in PA]

Well, I got the boat back this afternoon - yes the day after I dropped it off. Not bad turn-around for a dealer. It turns out the shaft bearing seals were slowly working their way out the back allowing for a slow leak. They pressure checked the unit, replaced the internal O-ring and both bearing seals and re-seated the needle bearing to it's proper location. They asked if the prop had any major nicks or dings which it doesn't but the previous prop that was on it had snapped off a blade by the previous owner. I still have the original prop and they said it could have been a problem from back then and just finally got bad enough to work it's way out that far. I will be keeping an eye on it but they didn't see anything to indicate a further problem. The gears were all OK and it's ready to run. Total cost $96.51. Not too bad for the service I received in my opinion.