Upper & lower unit water/drive oil leak in the bilge...

[rhillman75]

We took the boat out for the second time today since having the carb tuned in. Now that the engine and carb are strong...I open the hatch to throw some trash in the trash can to notice about a good 2 gallons of water/ drive oil in the bilge. The problem is that it had only been in the water for about 10 minutes. The reserve bottle was about half way below the line so I topped it off at home and at the point of looking at the bilge...all the drive oil was gone. Fortunately, I was able to operate the bilge to get everything out as I waited to pull the boat back out while a tournament was ending and about 20 boats were trying to dock. Talk about stressed out when you're wondering whats going to happen first...either your going to sink, burn up the bilge, or get it out. We did get it out and now I am wondering WTF? I know I had a friend replace my upper bellows some time back and I know he replaced the big o-ring at the end of the drive shaft that goes into the gimbal, but he did not replace the other 2 o-rings closer to the head of the upper unit (claiming that the 2 o-rings left in the gasket and o-ring kit). I know i had a slight leak from the lower unit earlier in the season and I would lose some drive oil as it sat during the week and I thought that that was do to the small o-ring in the lower unit but I have checked that 3 times since. I am planning on winterizing the boat tomorrow so my thought was to send it to the marina 30 miles away and let them rebuild it, but at what cost? My problem is pressurizing it off the boat. I am sure I can rebuild it coming from 10 years of transmissions and motors, but this is kind of new to me with this upper/lower unit. Any thoughts?

 

[duped]

Re: Upper & lower unit water/drive oil leak in the bilge...

The O rings on the drive shaft are NOT oil, or water seals and have nothing to do with your issue here. Water in the bilge would be a sure sign of leaking drive bellows... if you get even a small tear, it can fill a bilge fast.

If you have gear oil leaking into your bilge, the yoke seal on the upper gearcase is bad, oil is leaking into the bellows, and then into the bilge. If the U-joint bellows are in fact torn, your water is coming in through there too, and ruining your gimble bearing. You can visually inspect the bellows now. But it would be my advice to pull the drive off and get a real look at things, its a good thing to do for winterizing anyways.

Whatever you do, DONT use the boat as is. If you are leaking gear oil OUT, water is getting IN. And that can be a disaster. The yoke seal leak can be deceptive because it trickles down when the boat sits, and makes it appear as though the seal near the waterpump is bad, when in fact its running down from the yoke and through the shift shaft.

 

[rhillman75]

Re: Upper & lower unit water/drive oil leak in the bilge...

The yoke seal leak can be deceptive because it trickles down when the boat sits, and makes it appear as though the seal near the waterpump is bad, when in fact its running down from the yoke and through the shift shaft.

I was kind of wondering about this due to the inspections I did tonight. Its kind of hard to explain from my standpoint, but if you have it in trailer position and look up (on your back) at the point where I call the "90 degree arm on the lower unit that goes into the u-shape shaft on the upper unit" I visually see a drop of drive oil that accumulates there. If you wipe it...it re-appears after a couple of seconds. I am planning on having someone rebuild the upper and lower unit, but since I do not know which "kits" I need... I am at a loss for knowledge with all the seals and parts needed!

 

[duped]

Re: Upper & lower unit water/drive oil leak in the bilge...

Guessing it looks like this. ( gen 1 keep in mind )

Blown yoke seal dripping down the shift shaft.

When you pull the drive, you will be able to see a ton of oil around the yoke and in the u joint bellows. No need to have the whole thing re-built, I would just take the upper in and have the seal done and pressure tested. Why waste money. You still need to take a good hard look at your bellows too, that water is coming from somewhere...

 

[rhillman75]

Re: Upper & lower unit water/drive oil leak in the bilge...

Guessing it looks like this. ( gen 1 keep in mind )

Blown yoke seal dripping down the shift shaft.

When you pull the drive, you will be able to see a ton of oil around the yoke and in the u joint bellows. No need to have the whole thing re-built, I would just take the upper in and have the seal done and pressure tested. Why waste money. You still need to take a good hard look at your bellows too, that water is coming from somewhere...

Nice picture...kind of confirms the inevitable. Do you know the parts kit needed? While I have time with the outdrive off over the winter I am going to do the usual maintenance to the lower as well (impellar, ect). I know the u-joint bellows is new... I am just wondering if the "sealant" took or not. I know he had a hard time putting the bellows on while using the "super 3M weather stripping sealant (yellow type). I know he didn't use the "tool" and kinda of "worked" it on. Is it safe to remove the upper and lower drive before I start the winterzing process to the block by flushing the engine? I was planning on flushing the engine with the muffs with the plugs removed, and let it drain while I remove the outdrive, then fill with RV antifreeze. Then I was going to cover the outdrive opening with a piece of ABS plastic prior to storage.

 

[duped]

Re: Upper & lower unit water/drive oil leak in the bilge...

I have never done bellows on a Gen 2 drive, so my knowledge is limited. The U joint bellows are held on differently. You will be able to tell if it came loose when you pull the drive nonetheless.

I also dont know the parts kit. If you take it to an actual merc service center (which I would), they will figure it out.

You dont need to flush the engine with the plugs out, and its actually a bad idea. If water isnt flowing completely through the exhaust and out the drive, you will burn up the exhaust boots, flappers, and waterpump housing.

I just pull all the drains, chase them with a wire, pull all the cooling hoses, and call it a day. Air will never freeze, dont complicate things...

 

[achris]

Re: Upper & lower unit water/drive oil leak in the bilge...

Uni joint bellows on the Gen II are held on to the Gimbal housing in the same fashion as the Alpha One (Gen I) with a big hose clamp, but the bell-housing end is held in with an internal stainless steel lock ring. If the right tool wasn't used to put that lock ring in there is a high likelihood of it slipping out. That could be the source of water. The other possible place is the bottom of the exhaust Y-pipe. That model had hinge pin type exhaust shutters and they had a habit of breaking off, falling down the pipe, lodging at the bend and wearing a hole.... water in the boat.

HTH,

Chris.........

 

[rhillman75]

Re: Upper & lower unit water/drive oil leak in the bilge...

I am pulling the drive completely off tomorrow and covering the transom hole with ABS plastic that I cut to match the upper unit housing and bolts. My next question is... what seal kit do I need to get to rebuild the upper drive and what seal kit for the lower drive? I figured on just getting the lower water impellar kit but while it's all off... why not do the whole thing during the winter! What is the part number and the link to the exhaust bellow/tube that is being used now a days that does NOT connect to the actual drive housing. I figured I would just go with resealing the u-joint bellows and the non-attaching exhaust bellows tube for next year! Any thoughts?

 

[achris]

Re: Upper & lower unit water/drive oil leak in the bilge...

Unless you have ALL the right special tools for the job, forget it... Do a pressure and vacuum test on the drive to see if it needs to be done. If it doesn't need it, don't do it, you'll just introduce possible new problems... "If it ain't broke, don't fix it!!!" Never a truer word!

Chris........