Hey fellas, have a 91 merc black max 135 v6, #0C283114, just finished replacing the seals in the tilt cylinder. The oil I removed, looked nearly like a red'ish oil, almost like a motor oil mix with ATF. I have an old Merc repair manual on the way, but before it gets here, I want to start the purging process.

I did try "Google" FWIW, tons of pages, with tons of differing opinions, from Dextron 2- tractor hydraulic fluid, 10w/30-50 . Heck, if I kept reading, I would have probably found someone who swore by toothpaste and ketchup. Several folks said this and that was what was recommended in their merc manuals and it seems to run the gambit with new tech, so.... Trying to find the correct recommendation for this particular year model.

BTW, seals where solid and all seemed good until 2 year storage during the drought, cleaning her up I saw a bit of oil coming from the top of the cylinder and further the scraper and seal where free on the rod. Not a significant leak, but enough I didn't want to risk water in the system, or oil in the lake.

Thanks for your reply.

used Dextron for years but that trim isn't to picky as ya noticed with all tha different views!

Yes sir, last boat I had could go dex or 10w30, then I was told atf would mess with the seals, go figure. Opinions even differ depending on length/depth of freeze cycles in cold weather. I guess atf "may" separate the water and crack a unit at the extreme end of it.

if its got water in it ya got problems anyway!

That's a fact! Wish I would have saved the link, but read a mechanics post, he said he will not put atf in because water contained in the atf itself, can separate in super cold. New to me, never thought of, or heard of water being in an supplied "oil", sounds a bit far fetched to me (btw, he was in Minnesota iirc)

I can sure see water from bad seals, went through that with LU and carrier seal before.

never seen atf contain/make water myself?... guess they must get a lotta "busted" trans cases up there too!

What I thought, I don't think it is remotely possible to generate that much moisture out of an "oil" alone. Cane cutter I had, I used dex 3 for several years..

Just in case someone reads this later, got the service manual. It states to "use Quicksilver tilt/trim oil, or ATF, Type A, AF, Dextron 11"