What Are Your Thoughts On These Pics?

[tcbass]

These are pics of the lower unit of my 2000 115 horse Mercury 2 stroke. I have 2 questions.

 

One is that I noticed there are 2 holes at the top where there is normally only 1 for the lower unit oil. I opened them both up when I changed the oil and as I filled it, the oil came out of the top right hole. After a little while I put a little more oil in and closed it off. I have no clue what the other hole is for.

 

 

 

Do you know what the other hole is for?

 

 

 

 

Secondly, I noticed that there are 3 cracks in the upper part of the lower unit paint that I hadn't noticed before. When I bought the boat and motor last year it looked immaculate, granted I didn't look down there so I couldn't tell you if it happened before or after. When I was backing my boat away from the dock last year I hit a rock that took that nick out of the back of my skag. This is a very popular lake in my area and apparently kids throw rocks out there to do this to boaters and laugh about it. I didn't know until it was too late. So, I don't know if the cracks were from before or from after I crashed into the rocks. I haven't noticed anything leaking from the motor when it's in the water or out of the water and it runs fine. However, when I did change the oil today it did seem to be a little low. I don't know if that's because it leaked out or the previous owner didn't put enough in. When I took the lower unit oil bolt out I noticed there was a few tiny bits of metal, and I mean tiny, on the bolt. Not like shavings, but little dots of metal. That made me worry a bit. Granted, it was a very minute amount of metal. I don't know if the metal could have come from the crash, not enough oil in the lower unit, normal usage, or from the bolt being cross-threaded (although it doesn't appear to have ever been cross-threaded). There was probably 1/2 a quart of oil or so that I drained out.

 

 

 

Do you know if these crack looks bad enough to have damaged the motor?

 

 

Cracks in lower unit:

 

 

 

Two bolts at the top of the lower unit instead of 1:

 

 

 

[00 mod]

Skeg spot is no problem.

 

Cracks are nothing to worry about, yet I would watch them to make sure over time they don't get worse.

 

Minute metal is normal.  When it gets worse, is when there is a problem.  If you have ever cut open an oil filter to look inside, I am sure it is much worse than what you saw.  Metal objects turning on other metal objects cause this, hence the need for oil.

 

No clue about the other hole?

 

Jeff

[WIGuide]

I'm not sure about the hole. I'd keep an eye on the cracks. To echo 00mod, you don't need to worry about the metal. It's normal, and actually more unusual not to have any. The backs of the lower unit bolts usually have tiny magnets on them for that purpose. It catches the shavings so they don't keep going through your gears and lower unit grease. 

[martintheduck]

The other hole clearly states its purpose ---- "vent"...Now, what does that mean? I don't know.

[Christian M]

One hole is for water, the other is a vent, all 2 stroke mercury outboards have these holes. If you ever have questions about your outboard, you can just call Mercury Marine. I recently tuned up my Merc & they were really helpful