BII outdrive oil leak?

[Go Aweigh2452]

Background: I had the shop replace my gimbal bearing and serviced the outdrive at the same time for the end of the season. We used the boat twice since then for short runs. I garaged the boat afterward and lowered the outdrive. I noticed a little outdrive oil under the drive. I raised the outdrive so I can pull the boat out and prepare for this weekends Christmas parade/show and noticed black oil dripping out of the lower unit vents when the outdrive was put in the trailer position. I also noticed my gear oil reservoir is almost at the add limit which is not normal as I keep it at the fill limit.

So the question of the day is...

What possibly caused this drip?
http://www.bremertonnjrotc.com/goaweighto/outdrive/IMGP3453.JPG

http://www.bremertonnjrotc.com/goaweighto/outdrive/IMGP3454.JPG

[Pegasis]

Assuming the shop separted the lower gear case from the upper portion, they may have forgotten to replace the o-ring seal between the two pieces.

[SomeSailor]

Assuming the shop separted the lower gear case from the upper portion, they may have forgotten to replace the o-ring seal between the two pieces.

They wouldn't (shouldn't) have split the case (upper/lower) to change a gimbal bearing. There is an o-ring that may be pinched where the leg attaches to the bell housing but that wouldn't be anything connected to that area (that's your raw water intake). I'd be worried that water trapped in the leg may have frozen and cracked the leg? I've heard of people having issues when not lowering the leg after getting home and then having a cold snap.

A pressure / vacuum test would show you where it's coming from. You can get a hand pump at Harbor Freight.

[2859er]

There is an o-ring that may be pinched where the leg attaches to the bell housing.........

Yes. I pinched that o-ring valve seat once and got an oil leak, but oil didn't leak from the raw water intake slits, it leaked from up higher on the drive near the valve.

[Go Aweigh2452]

There is an o-ring that may be pinched where the leg attaches to the bell housing but that wouldn't be anything connected to that area (that's your raw water intake). I'd be worried that water trapped in the leg may have frozen and cracked the leg? I've heard of people having issues when not lowering the leg after getting home and then having a cold snap.

A pressure / vacuum test would show you where it's coming from. You can get a hand pump at Harbor Freight.

I have no water intake from the outdrive. My raw water comes from a thru hull...

I doubt the last freeze was a problem since the boat was garaged and the garage did not go below freezing for more than a few hours until I got the genny going... in any case, I keep Costco water bottles on the garage floor and they were not frozen at all. That is my back up as to how cold it can get in there.

[SomeSailor]

I have no water intake from the outdrive. My raw water comes from a thru hull...

There's still a water intake there. On boats that don't use the leg, there is a rubber cap over the incoming pipe from the leg. Not sure what else it could be or more importantly what could have caused it. That's a strange place for gear lube to leak. I could be the front seal leaking and then seeping down and in through the water intake, but there really doesn't seem to be a path that I can think of that way.

[The Peddler]

Is it sticky? Sticky could indicate gear lube.

Are you sure it's a lubricating fluid? Sometimes the raw cooling water, mixed with exhaust can look like oil. It's not uncommon to see some water leech out of the exhaust system. Did you or the shop that did the recent work spray any "fogger" into the motor? This is most-often when you'd see something like pictured.

[Go Aweigh2452]

I verified, the lower unit was not taken off when the gimbal bearing was replaced. The green gear oil looks like it is coming out of the water intakes on the outdrive. I had about 1-1.5 oz on the garage floor. I checked the "black oil" which turned out to be the green gear oil and it really looks like it is weeping out of the water intake louvers. Maybe it was overfilled and maybe it had an air bubble in the system. I added about an oz of oil to the reservoir which was still indicating between the add and full mark. I'll check it again when we pull the boat on Sunday.

[Randygh]

If oil is leaking from anywhere on the outdrive, doesn't that mean there is a possibility that sea water can leak in? How likely would it be the outdrive oil could become contaminated with salt water?

[Go Aweigh2452]

If oil is leaking from anywhere on the outdrive, doesn't that mean there is a possibility that sea water can leak in? How likely would it be the outdrive oil could become contaminated with salt water?

Not anymore than a 2 stroke would put in the water. When I dunked her, i did not see any oil slick so maybe it was an overfill? Will check when we pull her Sunday or Monday...

[fishaman]

Doug,

The more I think about your particular scenario (drive out, then back, leg raised, oil shows from the vents, reservoir empty), the more it looks like most probably you have a problem with the o-ring around the plastic valve between the drive and the bellhousing. If this ring is compromised, the oil will leak from the reservoir and find its way to the water passage below it. The good news is that all that required to repair is a $6 outdrive seal kit. I would also change the outdrive oil, or at least would drain it and inspect for white streaks... Make the guys at repair shop do it, most probably they have not glued the o-ring correctly with bellows adhesive in the groove before installing the drive.

[Pegasis]

When they replaced the gimbal bearing, they had to remove the outdrive from the transom shield. Could be a gasket or seal problem in that area and the oil is dripping into the water port in the leg.

[SomeSailor]

The oil dripping from the water intakes is what is most troubling. I can't see how oil could be escaping from the "oil side" to the "wet side" with the casting the way it is. Take a look at the attached picture.

1451

[Randygh]

I'm not concerned about a couple drops of oil in Puget Sound, but I was wondering if the oil leak could result in salt water intrusion into the outdrive gear clusters?

[SomeSailor]

I'm not concerned about a couple drops of oil in Puget Sound, but I was wondering if the oil leak could result in salt water intrusion into the outdrive gear clusters?

Oil out = Water in. Especially when the drive warms up, and then you shut her down and the cool down starts. Contraction will draw water in just as the difference in specific gravity will. I'd be curious where it's coming from. That water intake is plumbed even if not used. There's no opportunity for oil to make it to there through natural plumbing that I can think of. A pressure test would show you where.

I'd run one before pulling it to, that way you'd not lose track of what it is.

[fishaman]

1452

If the o-ring around the valve (marked by black arrow) is shot, the oil will leak from the reservoir between the bellhousing and drive. If the oil will follow the green arrow path, it will leak from the grills.

[SomeSailor]

1452
If the oil will follow the green arrow path, it will leak from the grills.

But, you're now assuming TWO O-rings didn't seal? It would have to leak OUT of the gear oil system and then IN to the water uptake. Could happen I suppose. The scary thing about that would be the fact that leaving out BOTH O-Rings would make that more plausable. But if your mechanic did that... hmm...

A pressure test would be spewing oil with a couple of pumps.

http://www.harborfreight.com/media/catalog/product/cache/1/image/370x/9df78eab33525d08d6e5fb8d27136e95/i/m/image_673.jpg

[fishaman]

But, you're now assuming TWO O-rings didn't seal?

Doug might not even have this second o-ring. His water pickup is from the thruhull, so most probably the tube between the bellhousing and transom shield is removed, and transom shield is plugged. In this case there is no need in the o-ring around the water pickup, so they probably did not care to install it. I would not install it if I had a similar setup. Hopefully that is the case, and valve o-ring replacement will solve the problem.

Or, maybe some stud nuts were not fully tightened... or overtightened... even scarier...

[SomeSailor]

Doug might not even have this second o-ring. His water pickup is from the thruhull, so most probably the tube between the bellhousing and transom shield is removed, and transom shield is plugged.

The water uptake should be intact. I helped Erik remove his entire bell housing assy (he has a sea strainer) and they leave everything connected. There is merely a small rubber plug in the line stub.


In this case there is no need in the o-ring around the water pickup, so they probably did not care to install it. I would not install it if I had a similar setup. Hopefully that is the case, and valve o-ring replacement will solve the problem.

I can see that logic, but it's hard to believe a puddle of oil coming out of the water intakes... wouldn't be at least seeping out elsewhere.


or overtightened... even scarier... That sounds more plausible. Tough one though. Makes no sense seeing oil coming out there at all.

[Pegasis]

Could be oil/grease from the gimbal bearing getting into the water port. If the seal between the input shaft and the water port, between the red arrow and the green arrow in the picture above, were pinched, the oily substance from inside the bellows/gimbal bearing could migrate into the water intake. A pressure test will not find this leak.

[SomeSailor]

Could be oil/grease from the gimbal bearing getting into the water port. If the seal between the input shaft and the water port, between the red arrow and the green arrow in the picture above, were pinched, the oily substance from inside the bellows/gimbal bearing could migrate into the water intake. A pressure test will not find this leak.

Problem is he's losing gear lube, and that's gear lube on the floor... not grease.

Also... if it were grease migrating OUT of the gimbal bearing... he'd have salt water migrating back in.

There's just no easy way for oil to get OUT of these drives... without water getting IN. There is positive pressure (0.44 psi) of water for every foot below the surface (Boyle's Law). For every 33 feet of water column, you pickup another atmosphere (0.44 psi per foot). So in example, if that water intake is located 2 feet below the surface, there is .88 psi of water pressure pushing IN.

You can't leak drive oil under that pressure. That's why a pressure test is necessary.

[Randygh]

Doug--have you unscrewed the outdrive drain plug to see if there is milky oil? If there is water intrusion, wouldn't the water mixed with oil settle to the most dependent area of the outdrive?

[Go Aweigh2452]

We pulled the boat today and I spent the day removing the engine oil, winterizing again and cleaning. Will finish cleaning the hull tomorrow and she goes back into the barn. At that time I will check the outdrive gear oil. However, I noticed no drop in the reservoir level.

[SomeSailor]

Maybe when he pulled it to get to the gimbal bearing he spilled some gear lube and it went down into your water uptake and just never got it all cleaned up? When you got home it finished dripping?