Lower Unit Leak! Leaving in a couple of days and now this...

[FishingKY]

2005 Opti 200... 1b176241

Went out to the garage to start the mower and noticed lower unit oil (blue'ish green) dripping from the nose cone inlets. After further inspection I could see where it ran down the side water inlets, too. After hours of research and surfing posts I have done the following...

- Drained L/U fluid and about 5 table spoons of water came out then the lube.
- Inspected inside the lower cowl and no signs of oil at all
- Pulled prop and no lube inside L/U hub
- Dropped lower unit and saw dirt film on top of unit, dirt film inside drive shaft (exhaust section), no oil dripping from up inside motor area, oil or grease on top of drive shaft
- Went to perform a pressure test and it will not hold enough air to soap up seals... I can hear air immediately escaping from what seems to be the side water intake ports

Any help, next steps, or diagnosis with part numbers would be greatly appreciated. I've done so much to this "new to me boat" and now that I have the set up dialed in and I' about to leave for Dale Hollow this happens. Sorry for ranting.

[FishingKY]

Need to mention that the drive shaft itself seemed to be dry and no sign of the brown DFI oil I use. Could the rough waters of St. Claire have popped a seal while running, or the terrible Detroit roads getting to and from there?

[06 SB]

I may be wrong but that looks like an SEI Lower unit not an OEM...

[FishingKY]

I ask the original owner if it was the original factory unit and he said it was the L/U that came on it when he ordered it. I am guessing it's OEM, but how can I be certain.

[Savage]

I would inspect the drive shaft oil seals under the water pump base.

[FishingKY]

Are these also called the prop shaft oil seals? If so, are there any special tools required / recommended? I've done everything from engine rebuilds to splitting a tractor gear case for clutch work ---is there anything or any reason I should not attempt this?

If I simply get this and install it is there something else it could be that wont be in this kit.... Gear Housing Seal Kit 26-816575A4

Sorry for all the questions, at this point I'm just waiting for the next thing to go wrong.

[billnorman1]

I would inspect the drive shaft oil seals under the water pump base.

Either that or the shift rod seal. I just changed the driveshaft seals on my outboard. It wasn't a Mercury (Suzuki 175DF) but I had the same symptoms. Those two are the only seals that I know of to the L/U that are high. Oil leaks go down and back, at least they did on airplanes when I worked on them.

[fishnfireman]

Drive shaft seals or shift shaft seal would be my guess..
.
You asked "

Are these also called the prop shaft oil seals?"
If your asking about the seals Savage was talking about in the previous post. NO.. The drive shaft seals are easy, just make sure they are placed correctly. They are both the same--- one points out the bottom seal points in.

[Savage]

Drive shaft seals are on the DRIVE SHAFT
Prop shaft seals are on the PROP SHAFT

As stated, I would start by inspecting the drive shaft seals, since you state that you hear air coming from the water pump intakes, when pressurizing the gear case.

[FishingKY]

UPDATE

Savage, Fishnfireman, and Billnorman1... spot on guys!! Pictures of what I found. Not sure what actually caused this but I did find a small rock in the impeller housing. I just changed all this out in the spring, too. While I have it down should I go ahead and replace the shift shaft seals? Talking with the original owner they have never been done.

[FishingKY]

[FishingKY]

[Savage]

If it were me I would install the bolt on Drive Shaft Seal Carrier. Two holes will have to be drilled and tapped in the lower unit to convert to this type of seal carrier. Looks like the gear case was overfilled with gear lube.

[fishnfireman]

While I have it down should I go ahead and replace the shift shaft seals? Talking with the original owner they have never been done.

I would.. While you have it off.

[FishingKY]

Ok, so I replaced the water pump, impeller and all gaskets. Replaced shift shaft gaskets and seal. Pressure test shown a very slow leak on the inside curve of the shift shaft housing gasket. Slightly tightened bolts to see if that would work, and no.

Pulled shift shaft housing back off and applied an ultra light film of black RTV sealant to both sides of gasket. Reinstalled housing and torqued to specs. I will pressure test in the morning. Is what I did a bad move (the RTV sealant).

Lower unit is in neutral and when lift housing off the shift shaft lifted up about 2” but went right back in place... will this be an issue?

[Savage]

You should have replaced the drive shaft seal carrier.

[fishnfireman]

Yours looks different than mine so I did not say anything for lack of not knowing for sure. The Sportsmaster has a plastic housing with an O-ring and a oil seal for the SS.
Wish I had told you that I have had better luck with getting the whole assembly for both the SS and the drive shaft. The drive shaft seal housing is also plastic and both are a PIA to change out just the seals.. Not to add that the housing will distort if it gets very hot when the old seals go out.

If the shift shaft went back down straight you should be ok..Its when it does not go back that its an OS moment.

[FishingKY]

Savage - I did. Replaced the carrier assembly, its o-ring, and the 2 oil seals. Also replaced the impeller, it's housing, and all gaskets. That part was not leaking any longer.

Fishnfireman - Pertaining to the SS... under the housing on mine it too has an o-ring I replaced that goes on a protrusion that goes around the SS. I also replaced the SS oil seal and the rubber washer that rides on top of it. Attached is a picture of what I replaced and an arrow pointing to where on the housing gasket there was soap bubbles during the pressure test.

Was using the RTV a bad move when used as mentioned in my earlier post -- lightly to help seal? We don't leave now until tomorrow so today I'll be testing it again.

[fishnfireman]

I would have tried the same thing in your situation. Cant see why the RTV would be bad.
Makes me wonder if the gasket was bad or if there is an imperfection on the casting or the new housing
Hope it works !! Always something with these dang things.

[EuropeanAM]

The o-rings and the shift shaft seal are what seal the GEAR LUBE passage. Gasket is sealing the water supply (low water pickups) and the Pitot Passage.

While pressure testing at 9-10 psi, check for leakage/bubbles AT THE PITOT FITTING ON THE GEARCASE (you may need to cover pitot opening on the leading edge with tape). There should be ZERO inter-connection between the gear lube cavity and the pitot passage (if there is, either an o-ring is leaking, OR THE HOUSING IS CRACKED AT THE BOTTOM OF THE PITOT CAVITY).