Trim pump fluid compatibility

[Evinrude Boater]

I replaced the cracked reservior tank and filled it with 10W-30. I have no idea what fluid was in it to start with. I've operated it several times but the fluid still goes creamy when operated then it clears up within 15-30 minutes of sitting. Initially I thought it was just air bubbles coming out of the system but now it gets me thinking the new oil isn't compatible with the existing oil. Any thoughts?

 

[Don S]

Re: Trim pump fluid compatibility

Milky usually indicates water in the oil.
If it looks milky in the morning, it's water. If it looks like oil, it's air.
If it turns pink, that means it had ATF in it before.
Mercruiser uses oil, not ATF. ATF will work, just as good as oil. But the two shouldn't be mixed.

 

[Evinrude Boater]

Re: Trim pump fluid compatibility

Milky usually indicates water in the oil.
If it looks milky in the morning, it's water. If it looks like oil, it's air.
If it turns pink, that means it had ATF in it before.
Mercruiser uses oil, not ATF. ATF will work, just as good as oil. But the two shouldn't be mixed.

Hmmm, must be air but why? Surely it doesn't take weeks and weeks of use to get the air out. I was using it for quite a while with low oil. Could that cause excessive air to accumulate?

 

[Don S]

Re: Trim pump fluid compatibility

You may have to run the drive full up and full down several times before you get all the air out.

 

[Bondo]

Re: Trim pump fluid compatibility

Ayuh,... The alternative is Water..... You decide....

I've never had an Issue with mixing oils like that,....and I mix oils...

Right now mine is sitting in the driveway waiting for a trim fluid change,...
Sunk the barge at the dock in a deluge,... Water in the trim...
It's got tractor trans/ Hyd. oil in it now,...
I'm going back to ATF,... It's much easier to see the level thru the reservoir...

 

[Jello Shot]

Re: Trim pump fluid compatibility

Are there advantages of using ATF over oil besides the visablity?

 

[Bondo]

Re: Trim pump fluid compatibility

Nope,.... It's still oil....