Gear lube resivoir-potential prob?

[Sherminator]

We went out for about 9 hours yesterday, a lot of High speed running 40+mph on the way back 3/4 of tank of fuel later we ran a long stretch of WOT for probably 5 minutes or so.. I could smell what seemed to be gear oil... well after we loaded up that evening i checked the resivoir and it was down about 1/2" below the add line and i was just about at full before the day started. I also have Gear oil running down the resivoir lines and dripping off the line under the engine. i took the resivoir off of the bracket and checked for leaks or cracks. i couldnt see anything. but i did notice a small vent hole on top of the resivoir cap. and it was wet. could my gear oil have gotten too hot and boiled or something? i dont see any oil leakikng on or around the stern drive either. any thoughts?

 

[John_S]

Re: Gear lube resivoir-potential prob?

If it overflowed the top of the cap, that would have been a big mess. Clean off the lines and recheck. Its leaking somewhere.

 

[Bondo]

Re: Gear lube resivoir-potential prob?

Ayuh,.........

When oil is Heated,.... It Expands.....And it's got to go Somewhere......

Is it still Clear Oil, No Clouding from Water,..??....

 

[John_S]

Re: Gear lube resivoir-potential prob?

The fill line is a ways below the bottom of the fill cap. It would be hard to believe that "normal" oil expansion would cause it to overflow. If it was overfilled to begin with, maybe, but wouldn't think it would be able to over flow enough to drop below the line.

 

[Sherminator]

Re: Gear lube resivoir-potential prob?

thats what i thought, the full line is about 1 inch below the cap, the only onther thing that was "wet with oil" was the sensor that has the 2 wires comming out of it, i can see the rubber gasket isnt super tight in there.. but i hate to go tightening it up and have it strip or break..ill ge out and get a pic of it here quick.

 

[Sherminator]

Re: Gear lube resivoir-potential prob?

here is a view from the top down.

 

[Sherminator]

Re: Gear lube resivoir-potential prob?

view from the top

 

[Sherminator]

Re: Gear lube resivoir-potential prob?

view from the bottom

 

[Sherminator]

Re: Gear lube resivoir-potential prob?

view out of the bracket that holds the resivoir

 

[HT32BSX115]

Re: Gear lube resivoir-potential prob?

A lot of times when the bottle overflows during running it's caused by excessive heat. It's normal for the drive to get warm.... but if it gets hot enough it will vaporize any water in the drive



Oil with water in it doesn't lubricate as well as pure oil so it could make it worse (i.E. more heat)

When it heats up enough the water in the oil turns to steam and pressurizes the drive.

Since the pressure has to go somewhere it either blows the seals and/or pressurizes the bottle.... and if the cap leaks it comes out the cap. If the cap doesn't leak the bottle blows up like a balloon, blows the cap or hose off or bursts the bottle.

Either way. make sure your drive is filled properly. and try draining a little at the bottom to see if there's water in there...(although the water/oil will be pretty much emulsified by now....When you get enough water in the oil it'll start turning lighter in color.


You probably should change the drive oil and pressure check the drive.



Regards,



Rick

 

[Sherminator]

Re: Gear lube resivoir-potential prob?

by checking the oil, would water come out 1st or oil? dont remember if oil is heavier than water.

 

[Don S]

Re: Gear lube resivoir-potential prob?

If you are using the Merc Hi Performance gear lube (Blueish Green) It will mix and become milky. It's got additives to prevent it from seperating.

 

[gejandsons]

Re: Gear lube resivoir-potential prob?

Oil floats on water.
Good luck
Outboards only.

 

[jastacey]

Re: Gear lube resivoir-potential prob?

This makes a good case to install a drive shower, Mercrusier drives always run hot when pushed hard.

 

[Sherminator]

Re: Gear lube resivoir-potential prob?

ok this is all starting to make sense now!! what is the best way to check that plug? if it take it out wont all my oil come dumping out? or can i just unscrew it a little and "some" will come out? yeah speaking of heat, i did have it really trimmed out.. all the way up on the trim and then clicked the trailer trim just a lil too.. just about to the point it was going to cavitate but it didnt.

 

[John_S]

Re: Gear lube resivoir-potential prob?

" i did have it really trimmed out.. all the way up on the trim and then clicked the trailer trim just a lil too.. just about to the point it was going to cavitate but it didnt."

You should not be running in the trailer position or you will cause pre-mature failure of the U-joints.

I think it would be very unusual to be near the fully trimed out position while planed out. I only run in that position while going through our channel at 1000rpms and it is just to reduce ground contact posiibility.

 

[Sherminator]

Re: Gear lube resivoir-potential prob?

i know what your talking about but to get my max speed i need to be trimmed out.

 

[Sherminator]

Re: Gear lube resivoir-potential prob?

ok guys, draining gear lube as we speak. some of it is greenish gray, and some of it is black, doesnt smell like new stuff either. when i refill, bottom to top, should the lower unit but all the way down or up? i was guessing all the way down because then the top hole would be almost directly above the bottom.. what is right?

 

[flyinghi5]

Re: Gear lube resivoir-potential prob?

I had the same problem just recently and come to find out it was the seals on the lower unit shaft. It never showed any signs of leaking when just sitting but when I put it in the water and put it under load while skiing or large tube pulling I would go through a full fill. Like some are saying, when it heats up it gets hot and expands and its got to go somewhere, mine was through the shaft seal. Replaced upper and lower shaft seals and the last 2 times out, no oil loss.

 

[Sherminator]

Re: Gear lube resivoir-potential prob?

thats a thing to remember flyinhigh, however right at this moment i need to know if i should fill the stern up with the motor down or up.