What kinda oil for tilt/trim system

[gros21]

It's a 96 40hp merc and when get it I want to change/top up this up it it easy as lifting all way up locking motor up unscrew bung and then top up then lift/lower a few times.
What kind of fluid should I use?

[FNQCairns]

I looked into it a few years ago

http://www.ausfish.com.au/vforum/showthread.php?t=109477&highlight=military

I ended up using the seastar (military grade) branded stuff for the steering but I have for ever ran the mentioned auto trans fluids in my trim and tilt, little slower due to the 25% or so increase in weight but that's the extent of the drawbacks noted so far.

From memory (so DYOR) all of the oil info in that thread also applies to trim and tilt, the military grade (very finely filtered) oil is the exact same stuff (specification) light planes use to raise and lower landing gear.

[FNQCairns]

When the engine is down the rams etc are retraced, these displace oil to the resevoir, this position marks the full level.

I don't have the merc but when I do it I open the reservoir, wait for the oil inside to debubble if I used the trim motor recently, top it up, close the reservoir and bobs your uncle. if it is already low enough to cause function problems then do the same a few times with runs up and down, check and debubble often until the level stabilizes.

[gros21]

Don't think it's power trim (well it had no wires) I'll just ATF from super cheap. I'm just getting stuff while I'm in Gladstone as they have more than rocky.
Got 4l valvoline 2stroke oil with free measure cup from bcf ($25)
Quicksilver gear oil from merc dealer ($34 for 1l with pump)
No just got to get some ATF I'll try to get some decent stuff then I'm set for a minor service this weekend, build new casting deck during week
Then lisence weekend after next then barra barra and more barra

[gros21]

http://www.marinepartsman.com/tilt-angle-and-power-trim-and-tilt-systems-in-mercury-and-mariner-outboards.html

Not exactly my engine but close enough

[FNQCairns]

Oh Ok! if it's not power trim then you may not need to worry about oil, could it be gas assist?? I am not famialr with the mercs.

Short of gas assist, it is a manual (muscle power) but all of them have a pin that sets the lowest leg in point with powered systems and with the other two the running trim.

[gros21]

it had a pin (I gotta replace it) but it looks identical to a electrical 96 merc one saw on eBay.
I'm pretty sure it's oil, would be good it wad electrical but not hooked up.
At the moment with it liftted then locked it slowly falls half way then ram stops it, hence me thinking it's low on oil.