On Transmission fluids and Hydraulics

I had vaguely similar symptoms with a car - Rover 214. Both the oil in the sump and the cooling water turned to mayo, without much change in level of either. Didn't show up 'til all power was lost climbing a hill. Blown head gasket.

Do you have any power loss?

Even if the level is the same, it doesn't mean that no water has gotten in the system. If water can leak in, then oil can leak out, and not change the level significantly. Check the seals on the hydraulic cylinders. Bet one of them is pushing out fluid on one stroke of the cylinder, and drawing in water on the other stroke.

The "thick froth and mayonnaise like deposits on the inside of the oil reservoir" does, sad to say, indicate water in the transmission fluid.

Sometimes a small amount of water in gear oils does not matter, if the application is a low-speed one (Land-Rover axle assemblies running in EP90 oil, come immediately to mind)

Are you using the outboard motor in seawater, fresh water, or water contaminated by heavy metals (a lake which has hydrothermal vents from volcanism below) ?

If not absolutely fresh water, and considering your housing will be an aluminium/magnesium alloy, it is important to clean out that reservoir, plus pipelines etc (flush well) otherwise corrosion shall set in, once started it corrodes the housing/oil lines/pump very quickly....

Re: On Transmission fluids and Hydraulics? The white stuff you are seeing is an oxide formed when an anti-wear components, added by the oil manufactures, is contaminated by moisture, the oil additive (possibly zinc oxide) will combine with any moisture in the system. When oil heats up any moisture in oil turns into a vapor and condenses on a cool surface, like a breather cap, or inside of an overhead valve pan when the engine cools down it will leave this white frothy goo. This is a good way to check a car engine to see if the engine has any coolant leaks from either a head-gasket or a small crack in the water jacket in the engine. An outboard engine tilt system operating in a (high humidity) environment will naturally form this type of goo (possibly zinc oxide) from (high humidity) air going in and out the reservoir every time the unit is operated, contaminating the hyd oil with moisture. This moisture eventually turns into white goo as it condensates on a cold inside top of the oil reservoir.

You have received some excellent replies, most if not all feel water is to blame, I can only say that is my thought too.....

Do a simple water test, draw off half a test tube of the liquid(s) and heat it up over a gas flame. If it "crackles", a bit like frying fries or eggs, it is about 99% certain that you have water in the oil....

Water does not have to "leak in" as someone mentioned, it can often happen that due to not running the motor long/hot enough, that the water is just humidity from the outside air....cars that only run a few miles each day suffer from this and when a long run is made, the water is driven off and the oil level drops suddenly and very dramatically....on car engines, you can often see the results on the inside of the oil filler cap.....UGH!!

Salad cream is not a lubricant!!! Its an emulsion!!

Oil and water DO NOT lubricate anywhere near as good as clean fresh undiluted oil!!

You will kill your motor/transmission.....

Donnieh seems to be a little more on track. The problem is with the "TILT SYSTEM" not with the internal combustion part of the motor. It's possible that if the system is operated frequently with humid conditions or water thats been splashed over the unit, you will eventually get this "Mayo" type deposits. Flushing out the system occassionally and refilling with fresh fluid can't hurt. Could just be a poor seal, o-ring, vent hole, any number of small leaks that could be at fault and allow moisture to enter.

I agree!

Moisture wil come in the tank with the air as the level of the oil is changing. Water can also enter the system on the pistonseals esspecialy iff the dustrings are bad or the piston is damaged.

The moisture wil kill the oil in the end. Take an oil sample at least once each year to control the cleanlyness.

Most systems are contaminated with dust and moisture. a good check, new oil or aditional filters can extend the lifetime off your pumps over 5 times! even iff we cant see anything on the hydraulic oil with our bare eyes.

Use a good tank breather, if the tank construction is strong enough use one with over pressure from 0,2 to 0,5 Bars. We let fresh air enter as the level sinks. As the level rises the checkvalve will close giving a little overpressure. This prevents the fresh air is constandly entering your tank.

Iff no overpressure is posibel because off a weank tank construction use a desicant filter.

If moisture can enter the cilinders opperate in wet conditions, use micro filtration. It will filter the defective dopes with water out off your system.

It will save a lot off money!!!!!!!.

It always has to hurt before people will listen.

Harmen Beskers

what great feelings not to alone anymore with your problems thanks to this great ideas exchanging medium of a site! To all replies thank you so much. in case you are interested, the Mayo deposits analised positive with water and the problem arose from a breach in the seals. Thanks again guys (and Ladies!)