Lower unit leak

[coolwhip]

Not sure if this is some type of exhaust port or not? Had just finished running boat and next day saw this on driveway. Normal? Thanks for any info.

Lower Unit 01.JPG
Lower Unit 02.JPG

[silvertalon]

I think thats a drain for your shift shaft cavity. As long as water drains out and not oil, everything's ok, IMO.

[coolwhip]

Thanks. Looked like combo of both. Very small amount after I got back from lake. Just wondering if it’s lower unit type of oil or if it’s stroke oil from possibly some type of an exhaust port?

[coolwhip]

I had also just recently drained and refilled the lower unit and there was no water inside the unit so hopefully just some type of over flow from filling it up all the way?

[EuropeanAM]

That opening is a drain for the entire cavity ABOVE the shift shaft seal carrier, water pump, etc. It's intended to allow WATER to drain (especially if the engine is tilted) in an effort to avoid water freezing in this area.

Hopefully you set the lube level correctly (JUST TO the bottom of the vent hole, and allow 1-2 ounces to drain off before installing the drain plug). Otherwise- it probably vented lube through the shift-shaft seal.

I would recommend that you get the case pressure tested if you have any reason to suspect leakage in this area. As mentioned above, over-filling is the #1 reason for seal failures in this area.

[coolwhip]

Good deal. Thanks.

[coolwhip]

So checked fluid and let out about an ounce or so. Looks little milky. Below are photos:

Oil1.PNG
Oil2.PNG

[apdriver]

See post 5. Bullet # 3. Water intrusion, for sure.

[coolwhip]

Ya, figured...can anyone point me in the right direction for the correct seal kit? Also want to replace water pump if I'm removing gearcase to replace the seals. Glad I caught the issue right after it happened. Thanks again.

[Savage]

You have TWO issues. The oil on the concrete is not oil from the gear case.

[coolwhip]

You have TWO issues. The oil on the concrete is not oil from the gear case.

Its same color and smell. What else could it be? From #5 post possible bad shift shaft seal.

[EuropeanAM]

You may be able to "see" evidence of where the leakage occurred- I would still recommend pressure testing the gearcase. Don't get into a complete seal kit unless you're going to start buying the special tools required for bearing carrier, propshaft seals, etc).

Shift Shaft seal carrier w/seal: 848836A1

Driveshaft seal carrier w/seals: 840836A2

Impeller Kit (without housing): 8M0100526

See Rhonda's post (pinned at the top of the Forum) for ordering info (you can also lookup and order right on the website at: www.mercurypartsonline.net ).

[coolwhip]

Thanks. I got both the impeller kit and shift seal carrier already at local dealer, but not the drive shaft seal. Do those normally go bad? The part looks very solid. The shift shaft seal not so much so can see how that one could be compromised. Thanks again.

[EuropeanAM]

Only way to know for sure is inspection and pressure-testing.

[coolwhip]

I got the drive shaft seal too

[coolwhip]

Here is the shift shaft seal. Definitely leaking.

ShiftShaftSeal.PNG

[coolwhip]

Replaced both seals and water pump. Tested her out and everything looks good. Thanks again for help.