Does this LU oil look bad/milky to you?

[Thirsty Endgrain]

Ran my '02 Merc 90hp 4 stroke on muffs this morning and saw what looked to be oil slick on both sides of the prop on the ground. Had checked my engine oil yesterday and it was a little low, so I filled.

Then this morning I decided to check the LU oil just in case that's what was on the ground. The oil was low which seems odd, I did a change when I bought the engine earlier this year, 6 months ago or so, so I know it was topped then. Have put appx 50 hours on it since then. Put about 20 pumps of oil in until it came through the fill hole at the top. I'd guess it maybe 8-10 Oz low or so. When the oil started coming out I noticed it looked a little funky, and maybe milky. What do you think?



Looks like I might be in for a little rebuilding. Was kinda figuring that if any oil was slinging from the prop that it would likely be gear oil. If it's engine oil that's a whole 'nother story. Leak down test checked out when I bought the engine.

 

[dingbat]

Ran my '02 Merc 90hp 4 stroke on muffs this morning and saw what looked to be oil slick on both sides of the prop on the ground. Had checked my engine oil yesterday and it was a little low, so I filled.

Then this morning I decided to check the LU oil just in case that's what was on the ground. The oil was low which seems odd, I did a change when I bought the engine earlier this year, 6 months ago or so, so I know it was topped then. Have put appx 50 hours on it since then. Put about 20 pumps of oil in until it came through the fill hole at the top. I'd guess it maybe 8-10 Oz low or so. When the oil started coming out I noticed it looked a little funky, and maybe milky. What do you think?

View attachment 373665

Looks like I might be in for a little rebuilding. Was kinda figuring that if any oil was slinging from the prop that it would likely be gear oil. If it's engine oil that's a whole 'nother story. Leak down test checked out when I bought the engine.

Yuk......full of water.
Did you use new washers on the drains screws?
If so, you need to pressure test and replace the leaking seal(s)

 

[Thirsty Endgrain]

I did not replace washers. Didn't have them at the time, and they looked in great condition. However, I didn't remove the vent screw when I did the fill (didn't know I needed to) and I did remove it earlier today, that washer did not look in as good of condition. I think I'll replace washers and do a pressure test as a start. Thank you.

 

[dingbat]

I did not replace washers. Didn't have them at the time, and they looked in great condition.

They always look "great".......then they leak

 

[Thirsty Endgrain]

They always look "great".......then they leak

Lesson learned

 

[Thirsty Endgrain]

Though if oil is in fact slinging out from the prop then it would indicate oil seals and not drain/fill plug. Ordered a LU rebuild kit just to have it on the way in case. It was $50 so I'll keep it even if it's not the issue. Will post pressure test results tomorrow.

 

[merc850]

Looks like the oil is coming from the top of the LU from the waterpump base I would remove the LU replace the impeller (if it's old) and do a pressure test.

 

[Thirsty Endgrain]

Looks like the oil is coming from the top of the LU from the waterpump base I would remove the LU replace the impeller (if it's old) and do a pressure test.

That it is. I have the fill plug removed and was pumping oil in from the bottom. When I noticed it looked a little milky I stopped and took a pic. I am doing a pressure test shortly once it warms up a little outside.

 

[airshot]

That it is. I have the fill plug removed and was pumping oil in from the bottom. When I noticed it looked a little milky I stopped and took a pic. I am doing a pressure test shortly once it warms up a little outside.

That is how they should be filled....pumping from the bottom up until the oil comes out the upper vent plug ! In tour initial fill from 6 months back, you didn' mention removing the upper vent plug.....did you force oil into the LU and damage the seals??

 

[Thirsty Endgrain]

That is how they should be filled....pumping from the bottom up until the oil comes out the upper vent plug ! In tour initial fill from 6 months back, you didn' mention removing the upper vent plug.....did you force oil into the LU and damage the seals??

It has a drain plug, a fill level plug, and a third vent plug, so it might just be semantics if there's any confusion.

I removed the fill level plug but not the vent plug, and was of course pumping from the bottom. I wouldn't imagine that just because the vent plug was in place during the fill that I could've done damage, air can still and did escape from the fill level plug until I reached it and fresh fluid came out.

 

[airshot]

It has a drain plug, a fill level plug, and a third vent plug, so it might just be semantics if there's any confusion.

I removed the fill level plug but not the vent plug, and was of course pumping from the bottom. I wouldn't imagine that just because the vent plug was in place during the fill that I could've done damage, air can still and did escape from the fill level plug until I reached it and fresh fluid came out.

Wasnt aware your had 3 plugs, all my motors over the years have only had the bottom fill and the top vent. By all means use the fill level plug as the mfgr requires. I stand corrected,......

 

[Thirsty Endgrain]

Alright well I just resealed the whole LU just to be safe. Oil that came out actually didn't looks very bad or milky. Not sure why that little bit at the drain looked funky. It did seem like the upper/lower oil seals below the water pump were failing, the bearing surface had a little rust, and there was some milky oil there. Shift shaft lpooked good but replaced it of course. Prop shaft seals also looked good, there was a bit of old fishing line in there, but didn't seem to have affected the seals.

One thing I discovered by accident, luckily not too bad of an accident. I was working on it late last night to get it done, after replacing the water pump/shift shaft seals I unbolted the bearing carrier, and then decided to pressure test before pulling it. I also was not feeling like going and getting my puller and rigging it up. So I apply 10 PSI and notice the carrier slowly start to push out. AH hah! I was then able to put a firm hand against the prop shaft/carrier assembly and slow pull while keeping good pressure on it to remove the assembly. No puller needed! I wouldn't sanction doing this without a helper. If that thing had blown out it could have caused serious harm or damage. 10 PSI is a lot of pressure in that circumstance.

Anywho, it's all back together, held pressure, fresh oil, etc. All happy now.