gear lube monitor leaking?

Happy Dayz

Active Member
Jun 26, 2017
543
Sarasota, FL
Boat Info
'06 260 Sundancer, 6.2, BIII, Kohler 5kw
79' classic Kona Family Cruiser jet boat..
Engines
6.2 w/ BIII, 502 w/ Berkekley
so my outdrive was rebuilt to some extent prior to purchase by after the survey...

now it appears my gear lube monitor is leaking (Merc 6.2) ... or overflowing?

seems the oil line connections and monitor sensor are tight...

but get oil leaking from it into bilge... i swear it is overflowing through breather in cap.

anyone else have the same issues?

 
its possible when outdrive is in use it gets warm and oil expands and burps. siphon so level is between add and full line.
 
If the bottle is full look at the oil to see if it is milky ( water in the oil )
I had the same problem and it turned out to be the bellows was bad.
The mechanic said on Bravo 3 drives they have a one way seal at the top were the U joint is connected that will allow water to get into the drive and oil can not get out of drive, So if the bellows is leaking water into the u joint area then the drive will suck the water into the drive and force the oil back up into the bottle and it will overflow.
My fix was all new u joints and bellows and problem was solved.
 
There's more than a gasket on the cap, it's got a rubber valve, that can fail. Lower your oil level to the add line and see what happens when it gets hot.
 
If the oil is coming from the cap, it was overfilled or is getting water in the drive
 
I just got my boat back from the dealer who pulled the motor to install a new cool fuel system with pump and regulator. I also had them pull the drive and change the u-joints and shaft. I had the annoying beeping when the bottle gets low the very first time I took it out after all the repairs. I was hoping the system just had to burp because everything had been off and just reassembled but once I top it off before I go out I can go for about 4-5 hours and about 2-3 of actual run time before it starts beeping again.

I purchased a new bottle and installed it and refilled and had no issues for the day out. The next time it was low again when I went to start it before going to launch last time so I had to top it off again. I couldn't see any obvious signs of leakage.

I haven't been out out for a couple of weeks because of bad weather but today I saw gear lube lube under the trailer at the rear of the boat. I don't know if it is leaking into the bilge area and coming out of the garboard drain plug or coming straight out the drive yet. I will have to get down closer and take a better look tomorrow when it is better light. I have to get this resolved before going out again.
 
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Yep similar to your issue but mine takes days of running before low.. it's odd... appears to be overflowing but obviously is low when I look. I also find the oil where it drops down the engine into bilge... I'm also having overheating issues and wonder if when engine gets hot the drive oil expands such that it overflows.. then cools to a lower level?
 
You might want to check the elbow that goes from bilge through the transom. I fought with the same issue and found it to be defective. Once I replaced it, i have gone 5 years without any issues at all.
 
I had a little time to check on the leak and gear oil is definitely coming out from the garboard drain. I can't see anywhere in the bilge where it is leaking as it is pretty tight down in there. It must be behind the engine where it goes through the bellows.

Damn I hope the engine doesn't have to come out again to get to where I can fix this. If I just remove the drive can I get to the elbow and any other connections on the engine side from the outside?
 
Depends if you have the brass fitting or the plastic fitting. The plastic one can be changed without pulling the motor. The plastic one is a quick connect at the transom. check there for leakage . See page 4B-8
http://www.boatfix.com/merc/Servmanl/11/11b4r5x.pdf

Thanks much. At least now I know what to look for.

I will have to crawl in behind the engine and see how much I can get access to and whether I can spot any leakage.

I would have thought that the dealer would have done their job correctly!
 
Depends if you have the brass fitting or the plastic fitting. The plastic one can be changed without pulling the motor. The plastic one is a quick connect at the transom. check there for leakage . See page 4B-8
http://www.boatfix.com/merc/Servmanl/11/11b4r5x.pdf

Ok so I asked my son to come over today and be the contortionist to get behind the engine and take some pics so we could verify the type of gear lube transom fitting I have. Looks like I have the quick connect 90 degree plastic fitting. We took a picture that shows a black fitting with a grey push button to release it. I guess this is the good news as it can be changed without pulling the engine. The bad news is we couldn't see any leak. A couple of weeks ago I installed a new bottle and traced the hose all the way along to the stern and found no leak. I can't see that the fitting is leaking either but there is oil in the bilge.

The fitting is only $12 but should I also replace the hose and plastic clamps too?
 
If the bottle is full look at the oil to see if it is milky ( water in the oil )
I had the same problem and it turned out to be the bellows was bad.
The mechanic said on Bravo 3 drives they have a one way seal at the top were the U joint is connected that will allow water to get into the drive and oil can not get out of drive, So if the bellows is leaking water into the u joint area then the drive will suck the water into the drive and force the oil back up into the bottle and it will overflow.
My fix was all new u joints and bellows and problem was solved.

This probably happened on my boat. On survey before I purchased, it was noted that boots, bellows, gimbal bearing were loud. Seals for the outdrive were also bad because I kept losing gear oil all summer. Had to fill it every few weeks.

Glad to know what can cause this so that I can avoid it now that I'm installing a new outdrive.
 
Well I finally found out where my gear lube leak was. :(

I start the engine every week in the driveway on muffs but don't put it in gear every time to check and see if the prop is spinning.

I went to our launch ramp last weekend to try and take my brother and his kids and friends out and couldn't get the boat off of the trailer. No movement forward or reverse. I opened the engine cover and checked the shifter cables and they all looked fine as I thought maybe a clip or something had come loose. Ended up just winching it back on the trailer and taking it home to flush it out on muffs again.

Well I took it to the marina shop and they pulled the drive and said the driveshaft bellows was full of oil and it looked like the seal had failed. They could also see aluminum shavings on the driveshaft splines and it looks like my engine coupler is toast. Engine has to come out and this equals $$$$!. Damn!

I just had a new driveshaft with new universal joints and both inner and outer bearings installed and drive pressure tested last October.

The marina shop is the only authorized Mercruiser dealer here so I would hope they would do this correctly but....Is there a way to check that when they install a new seal that it is indeed installed correctly and it won't fail again? Any tricks of the trade to follow? Thx.
 

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