Anybody Continued to Operate w/Leaking Lower Unit Seals?

[minuteman62-64]

.... At least for a boating season?

1982 Mariner, 30 HP. Put back in service last year after 20 years in hibernation. Gearcase oil changed at that time and no evidence of water intrusion. Drained the lower unit yesterday and about 2 tablespoons of water came out, followed by milky brown gear oil. Only about 10 hours on the motor since last years service.

Based on other posts on this issue, I'm going to replace the vent and drain washers and replace the gear oil. Then take it for a run and see if there is still a water issue. However, because of the age of the motor I'm concerned that the seals dried up/deteriorated during the 20 years of sitting idle.

My question is, if there is still evidence of water intrusion, can I manage the situation to get through the boating season (through December around here). For example, a monthly drain/replacement of the gear oil? That would give me some time to think about how much $$$ I want to put into this motor and do some research on the DIY potential for replacing the seals.

Motor use is strictly salt water.

 

[geopgc]

Re: Anybody Continued to Operate w/Leaking Lower Unit Seals?

Yes but it was in fresh water. I drained the water and oil from the lower unit into a glass jar. Let it set for a few days. Water will settle and be visible. If water is less than 10% by volume I refilled LO with synthetic oil. This oil retains it's properties better than the mineral type gear oil when mixed with water. Many of the new LO oils for the larger outboards are synthetic or at least partially so. Then I monitored the oil for water every ten hours or so to see a pattern. If it stayed less than 10% water I ran it all season and had unit rebuilt during the winter. I've done this on two lower units. In salt water I might drain it once and retest it. If water showed up again I personally would fix it. Keep in mind I'm not a marine mechanic and I run my boats pretty easy, generally 15% below max rpm. You know what they say about free advice! While not a marine mechanic I do have a lot of experience with large industrial gearboxes and can confirm water/oil mixture in sufficient quantity is a poor lubricant and will cause gear tooth pitting pretty quickly because the mixture cannot maintain the required film when the two gear teeth are squeezed together. A LO repair at this stage may be considerably cheaper than a rebuild later in season if new gears and shafts are required. Resealing a LO is mostly labor, not parts. When gears need replacing it's all about expensive parts and most cannot be obtained from China... Again; free advice!
Geopgc

 

[wired247]

Re: Anybody Continued to Operate w/Leaking Lower Unit Seals?

Those seals are relatively easy to change without having to set up the gears.

 

[sutor623]

Re: Anybody Continued to Operate w/Leaking Lower Unit Seals?

Minute man, most of those oils will still function and provide proper lubrication with up to 10% water intrusion. Prop seals are great at holding oil in, but bad at keeping water out. I'd say that you are on the right track. Try it out again, monitor the hours on the motor and see how much water you take in. Check it every after a few hours of running and see how she looks. Only problem with this, is if you dont just go ahead and get it fixed now, you can do a LOT more damage!! Just keep a cautious eye out. I'm sure everyone on here will have a different insight.

What I do now a days is try and have an extra lower unit for each of my main motors. That way I can have a good unit at hand at all times and if I need a quick swap I can go for it. Then I can rebuild bad the L/U at my leisure. For a spring, summer, fall, winter-time fisherman like myself, there is no off season.

 

[CharlieB]

Re: Anybody Continued to Operate w/Leaking Lower Unit Seals?

Those seals are relatively easy to change without having to set up the gears.

Exactly.

Why even risk the possibility of causing greater damage, reseal it, pressure and vacuum test it, then forget about it til your next annual oil change.

 

[Sea Rider]

Re: Anybody Continued to Operate w/Leaking Lower Unit Seals?

Ruin your tail gears will cost much more than buying a complete lower kit which is not that expensive...

Happy Boating

 

[minuteman62-64]

Re: Anybody Continued to Operate w/Leaking Lower Unit Seals?

Those seals are relatively easy to change without having to set up the gears.

Assume you are referring to the technique of drilling holes in the seals and inserting sheet metal screws to pull against? As referenced in other posts on this site?

I wasn't sure exactly how this was done, and then I found this video (Part 1 of 3): http://www.youtube.com/watch?v=VZzwLU07v8U

It does look easy and doesn't require the special tools shown in my manual. I also found that the 4 seals and "O" ring for my motor will set me back the princely sum of about $20. Looks like the way to go if the new washers for the drain and vent plugs don't do the job.

Today I bought a pump for quart containers of gear oil. I had to buy an adaptor to fit the metric threads of my unit. Looks like the adaptor will lend itself nicely to hooking up an air hose for a pressure test.

 

[Mi duckdown]

Re: Anybody Continued to Operate w/Leaking Lower Unit Seals?

Your pressure test is only 3 psi Be carefull.??? what about the vacuum test??

 

[wired247]

Re: Anybody Continued to Operate w/Leaking Lower Unit Seals?

Nah. I just take them apart

Assume you are referring to the technique of drilling holes in the seals and inserting sheet metal screws to pull against? As referenced in other posts on this site?

I wasn't sure exactly how this was done, and then I found this video (Part 1 of 3): http://www.youtube.com/watch?v=VZzwLU07v8U

It does look easy and doesn't require the special tools shown in my manual. I also found that the 4 seals and "O" ring for my motor will set me back the princely sum of about $20. Looks like the way to go if the new washers for the drain and vent plugs don't do the job.

Today I bought a pump for quart containers of gear oil. I had to buy an adaptor to fit the metric threads of my unit. Looks like the adaptor will lend itself nicely to hooking up an air hose for a pressure test.

 

[minuteman62-64]

Re: Anybody Continued to Operate w/Leaking Lower Unit Seals?

Your pressure test is only 3 psi Be carefull.??? what about the vacuum test??

Yep, as I continue with my reading it appears that the vacuum test may be more relevant than the pressure test for my situation. I have a hand vacuum pump w/gauge that I bought years ago for work on my truck. That should do nicely with the acquisition of a couple of adaptor connections.

 

[minuteman62-64]

Re: Anybody Continued to Operate w/Leaking Lower Unit Seals?

OK, so I drained and refilled the lower unit. Put in new gaskets for the drain and vent screws. Took it out yesterday for a 2 hr. run.

This morning I popped the drain screw and tried to catch the initial flow in a clear plastic container. No evidence of water in the container, but I may have felt a little (couple of drops) on my fingers as I removed the screw. Opened the vent and drained the remainder of the oil - its a slightly milky blue color, no visable evidence of free water. Based on other posts it seems like it may take a couple of changes to get rid of the milky color even if no additional water is coming in.

It appears pressure and vacuum testing would be next, to get a definative y/n on the water intrusion. Apparently this means I'd have to drop the lower unit to see what's happening at the upper seals and shift shaft.

Here's my questions. 1982 motor w/original seals. Complete set of seals looks to be under $30. Looks like once I drop the lower unit I'm about half way there to replacing the seals. Would it make sense to go ahead and order the seals (all of them) before dropping the LU and testing. Then, with seals in hand, drop LU, replace seals, then pressure/vacuum test to verify repair and reassemble? Any downside to possibly removing and replacing a seal that might not be bad, since the existing ones are 30+ years old?