# Time for an experiment



## cathead (Nov 25, 2021)

This morning the thermometer was reading 2 below zero Farenheit so time for an experiment that has been waiting for some cold temperatures.  Last summer
I had removed five gallons of hydraulic oil from my skid steer as it was contaminated with water.  My plan was to let the oil sit quietly somewhere until
such time that the water had settled to the bottom of the container.  I decided outside would be the best place to store it so it had all summer with the
warm temps to separate out the water.  Today the oil looked like hydraulic oil is supposed to look, not all milky.  I decanted off the oil into a 5 gallon
container and was surprised that there what looked to be a brownish skiff of ice less than a quarter of an inch thick.  The oil looks good enough to
reuse so will save it for a later time.  Hopefully some of you will find this information useful.  I waited for the cold as any water would now be ice!

It's a nice sunny and cold day up here.  Happy Thanksgiving.


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## gun mechanix (Nov 25, 2021)

I have had to do that in the past as well, the water will separate and freeze, pour off the hydraulic oil into another container. Place the container near a heat source to warm the oil to thin it, then run it through a small electric transfer pump into a filter head with a 10 micron spin on filter, dumping it back into a different clean container and storing it out of the weather, or using it right away.


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## RJSakowski (Nov 25, 2021)

My Ford 8N used to be stored outside and water would enter the gearbox past the shift lever boot.  As a result, the hydraulic fluid was contaminated with water and look like a caramel milkshake.  I did the same as you did, setting the oil out behind the barn.  The water hadn't settled out after several summers.  When the water froze during the winter, the mix would take on the consistency of a slushy.  It has finally settled out after a couple of decades.

Our Nortrac tractor from Northern Tool came from the factory with water in the hydraulic oil.  The ice crystals clogged up the filer requiring a change of the oil.  The water settled out relatively quickly, probably due to the lack of additives and I would deem it usable although I haven't done so.

On another note, my new outboard has an annoying tendency to pick up water in the lower unit.  A pressure test and a vacuum test indicate the seals are good so how it enters is a mystery.  It isn't enough to cause any problems but still annoying.  I found that if I heat the oil, I can drive the water off although it takes the oil temperature up more than I would like.  I can boil the water out at a lower temperature by using a vacuum too.  I am not about to put the reclaimed oil back into a $7,000 outboard so it is mostly an experiment borne out of curiosity.  I do weigh the oil before and after to get an idea of the amount of water.  The Quicksilver  gear lube does have additives to mitigate issues with water contamination which may contribute to the degree of homogenization experienced.


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## Just for fun (Nov 25, 2021)

cathead said:


> This morning the *thermometer was reading 2 below zero Farenheit* so time for an experiment that has been waiting for some cold temperatures.  Last summer
> I had removed five gallons of hydraulic oil from my skid steer as it was contaminated with water.  My plan was to let the oil sit quietly somewhere until
> such time that the water had settled to the bottom of the container.  I decided outside would be the best place to store it so it had all summer with the
> warm temps to separate out the water.  Today the oil looked like hydraulic oil is supposed to look, not all milky.  I decanted off the oil into a 5 gallon
> ...


2 below zero is way to cold for this time of year! 

34° here in Northcentral Washington state.   I don't think we have got below zero in several years.

Good idea on salvaging the oil.


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## gun mechanix (Nov 25, 2021)

The water in your outboard is probably due to to condensation, if there are wide temperature swings and there is an air void in the case, the air condensates into moisture and runs down the inside of your case, and it will build up over time. While the unit is being stored venting the gearbox may alleviate some of this issue.


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## RJSakowski (Nov 25, 2021)

gun mechanix said:


> The water in your outboard is probably due to to condensation, if there are wide temperature swings and there is an air void in the case, the air condensates into moisture and runs down the inside of your case, and it will build up over time. While the unit is being stored venting the gearbox may alleviate some of this issue.


The lower unit is hermetically sealed. It is below water level during operation.  There is an air void in the case to allow for thermal expansion.  The seals are design to work with both positive and negative pressure.  My tests involve pressurizing  to 20 psi and  pulling 25" vacuum.  Both test should not leak down.. I believe that the standard is something like 15 minutes.  I let the test run for over 12 hours.

25" of vacuum is around -12 psi.  It is possible that the water pump is putting out more than that pressure differential and causing seepage past the seal.


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## Aukai (Nov 25, 2021)

If I remember correctly, when my boat had outdrives, I used synthetic gear oil, so if water got in the oil it still kept it's lubricity, and kept the lower unit safer. I used to put 700-1000hrs a year on them until I extended the hull, and went with shafts. That's what I was told anyway, not really sure if it was true though.


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## MrWhoopee (Nov 25, 2021)

I have a substantial quantity of reclaimed Vactra #2, which I use for chainsaw bar oil and way oil on the lathe. It was reclaimed from the tramp oil skimmers on the machines at my old shop. It was run through a 3 stage separation, each stage being a 5 gal. container with a tap a couple of inches above the bottom. The oil was allowed to separate in each stage for about a week before being drained via the tap and moved to the next container. It is a little darker than the original oil and carries no trace of the smell of rancid coolant. At $10+ for the cheapest bar oil, I'm glad to have it. Unfortunately, my supply has dried up.


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## f350ca (Nov 25, 2021)

Wonder if 20 psi and 25 inch of vacuum are setting the seals. It would only see a very slight pressure from the water column, maybe allowing a slight seepage.

Greg


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## RJSakowski (Nov 25, 2021)

f350ca said:


> Wonder if 20 psi and 25 inch of vacuum are setting the seals. It would only see a very slight pressure from the water column, maybe allowing a slight seepage.
> 
> Greg


Possibly, although I believe that I had also checked intermediate pressures.  I will be draining the oil out in the next week as part of the winterization process.


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## f350ca (Nov 25, 2021)

A common problem. Mercury had a positive pressure system for their inboard outboards. Was a tank that mounted inside the transom and a stainless line that fed the bottom drive. Gravity feed oil water difference couldn't have been much differential.

Greg


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## RJSakowski (Nov 25, 2021)

f350ca said:


> A common problem. Mercury had a positive pressure system for their inboard outboards. Was a tank that mounted inside the transom and a stainless line that fed the bottom drive. Gravity feed oil water difference couldn't have been much differential.
> 
> Greg


This is a 50 hp outboard. A vent tube which came up to the power head would help, as would a pressure reliefe system between the water pump and the gear box.  However, in forty years of Mercury outboards, this is the first time that I have had an issue with water in the lower unit.


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