So confused on mercruiser gear lube leak

[agallant80]

Last season I noticed some gear lube in my bilge. I could never find where it was coming from. On the last trip of the season I took the top screw off of the outdrive (bravo 3) and oil came out. I was good to go. I did my 160 mile trip but each way I had to fill up the reservoir, it had all leaked in to the bilge.

At the end of the trip when the boat was back on the trailer I filled up the reservoir again. Came back a week later it was all drained in to the bilge. I could never find the leak. I was reading the the quick connector (part #22-861163) that connects the reservoir hose to the through transom fitting (part #22-861150t02) could be a leaking issue. I replace it, fill up the reservoir again. Come back the next week and the bilge is filled with lube again.

At this point I look for a leak but can't find any gear lube on the reservoir and I don't see much on the through transom fitting (in fact I can't tell if its gear lube or spline grease that is back there). I pull the drive for the yearly service. No lube in the bellows so its not coming from there and the lube inside the drive has no water in it. I re-install the drive and it sit as is for a few months. Part of re-installing the drive was to refill it with lube which I did untill it came out of the top screw hole. I did not fill the reservoir since I knew there was a leak.

Fast forward to last weekend (few months later) I am messing around with the boat and decide to take the reservoir off, disconnect the hose and blow on it to see if I can see any lube coming out. I stuff a paper towel under the transom gear lube fitting and start blowing in to the tube. Its holding pressure and nothing ls leaking out so I reassemble everything and fill the reservoir back up but this time I don't tighten the cap I just put it on loosely and put fresh paper towels under the lube reservoir and through transom fitting to see which one is wet and where the leak is coming from.

I come back 4 days later and not a drop has leaked out. The paper towels are dry. The next portion of the experiment is to put new paper towels on, clean the cap and screw it on properly. I will be back to the boat in a few more days to see if it is leaking again.

My question here is does anyone have an idea of what is going on? Could the cap have been bad resulting in a built up of pressure which would force the lube to ooze out past some seals or fittings between the reservoir and through transom fitting?

 

[alldodge]

Last season I noticed some gear lube in my bilge. I could never find where it was coming from. On the last trip of the season I took the top screw off of the outdrive (bravo 3) and oil came out. I was good to go. I did my 160 mile trip but each way I had to fill up the reservoir, it had all leaked in to the bilge.

At the end of the trip when the boat was back on the trailer I filled up the reservoir again. Came back a week later it was all drained in to the bilge. I could never find the leak. I was reading the the quick connector (part #22-861163) that connects the reservoir hose to the through transom fitting (part #22-861150t02) could be a leaking issue. I replace it, fill up the reservoir again. Come back the next week and the bilge is filled with lube again.

At this point I look for a leak but can't find any gear lube on the reservoir and I don't see much on the through transom fitting (in fact I can't tell if its gear lube or spline grease that is back there). I pull the drive for the yearly service. No lube in the bellows so its not coming from there and the lube inside the drive has no water in it. I re-install the drive and it sit as is for a few months. Part of re-installing the drive was to refill it with lube which I did untill it came out of the top screw hole. I did not fill the reservoir since I knew there was a leak.

Fast forward to last weekend (few months later) I am messing around with the boat and decide to take the reservoir off, disconnect the hose and blow on it to see if I can see any lube coming out. I stuff a paper towel under the transom gear lube fitting and start blowing in to the tube. Its holding pressure and nothing ls leaking out so I reassemble everything and fill the reservoir back up but this time I don't tighten the cap I just put it on loosely and put fresh paper towels under the lube reservoir and through transom fitting to see which one is wet and where the leak is coming from.

I come back 4 days later and not a drop has leaked out. The paper towels are dry. The next portion of the experiment is to put new paper towels on, clean the cap and screw it on properly. I will be back to the boat in a few more days to see if it is leaking again.

My question here is does anyone have an idea of what is going on? Could the cap have been bad resulting in a built up of pressure which would force the lube to ooze out past some seals or fittings between the reservoir and through transom fitting?

You sure have had a time with this issue, and you might just be on to something. If the cap isn't allowing for expansion it would leak out the other connectors. Had a similar thing with a portable gen but it would die, and found out later it was drawing a vacuum.

Hope this is your issue

 

[agallant80]

Thanks all dodge. Funny thing was I have noticed when I pulled the drive before the system was holding pressure. even when I disconnected the hose from the reservior it would not stop oozing gear lube. I think all of this trouble may have been over a bad gear lube cap. I am going down there saturday. I wonder if the bilge will be full of lube again.

 

[alldodge]

Sure hope not

 

[Fun Times]

The cap is typically a problem while there is pressure buildup from being under way/load. Roughly there's 7-8 psi underway and if the black cap seal or the orange rubber one-way valve is defective, then the oil is known to flow out the top of the reservoir or cap. If the system isn't releasing pressure and the ambient air temperatures are changing up and down, then that may have an effect on the system tough it's unusual.....But wouldn't that be your luck with your boat? Just kidding.

At this point I look for a leak but can't find any gear lube on the reservoir and I don't see much on the through transom fitting (in fact I can't tell if its gear lube or spline grease that is back there).

As you know in the perfect world there should be no oil at all.
Found your old photo and posted below.
Are you able to clean the area?
Is this the same area you keep finding oil now?
Did the marine dealer fix it under warranty for you? Are you still under warranty?
The black click type clamps that hold the hoses onto the barb fittings sometimes need an extra click or two to tighten up the seal a little better especially at the reservoir.
http://forums.iboats.com/forum/engi...drives/8500647-gear-lube-in-bilge#post8520022
http://forums.iboats.com/forum/engi...monitor-elbow-quick-connect-fitting-22-861163

 

[agallant80]

Fun Times,

I put paper towels under every fitting so if its still leaking out I will at least know which end. I just think its strange when the cap was on it leaked like clockwork even after changing the fitting and when I left it off no leaks. Unless pulling the drive and putting it back on changed something, that is the only other thing that has happened.

 

[agallant80]

well just a follow up. Put the cap on and left it for a few days. Not a drop. Going to take her out next weekend. Hopefully she will hold.

 

[PeterB26]

Pull the leg and have a look inside your gimbal bellows. It should be 100% clean and dry. You might have a leak from the leg into that bellows and from there through the gimbal bearing into the bilge.

 

[agallant80]

Well I have no idea what I did but after pulling the lube bottle, cleaning, cleaning the cap and reconnecting the hoses I have no more leak. It just fixed its self.

 

[alldodge]

Dirt, either that or gremlins

 

[agallant80]

Just a follow up to this because it was so difficult to to diagnose. After some further experimentation is was a defective gear lube cap. The system was building up pressure and the vent hole in the cap was blocked. The pressure allowed gear lube to ooze out past the o-rings in the through transom connector and around the hose from the bottle to the through transom connector.

Who ever is searching google for this issue do yourself a favor and replace the gear lube cap first instead of running around looking at everything else.

 

[GA_Boater]

Hey agallant80 - Thanks for the follow up. It doesn't happen enough and can help answer future questions.