Tilt/trim oil advice for merc.

[mech1521]

I was at the local marina the other day, and asked them a question about the trim/tilt oil they use in their evinrudes and yamaha's and they told me dextron 2 trans fluid. Is this advisable for my 84 merc., they said it's ok for older mercs. as well. What do you guys think?

 

[Moody Blue]

Re: Tilt/trim oil advice for merc.

I've got an early 70's Merc that I use Dextron II in. No troubles at all. THis is a very common fluid to use, although I don't know if it is officially endorsed by Merc or not.

I also owned a '92 Mariner 40hp that also used Dextron II.

 

[RRitt]

Re: Tilt/trim oil advice for merc.

If the fluid in there now is red then use atf. If it is honey colored then use either ND motor oil or hydraulic oil. If it is a fresh rebuild then use what the manual says (otherwise some mechanic somewhere down the raod may add the wrong fluid). If it is a custom setup then hydraulic oil like they use in factories and robots and industrial equipment and commercial marine is the highest quality available.

Technically -
if you keep the PSI down the ATF works just fine. If you run the PSI up too high the the ATF impregnates the rubber seals and causes them to harden and split. The point where trouble seems to start is around 1500-2000 psi. Peak pressure is typically created at WOT when the prop pushes back down on the system.