Oil spec for '70s Merc trim and tilt

[Healey75]

Any suggestions please from the experts about oils, The Merc T&T pump (the type mounted inside the boat) on my engine calls for staight SAE 20 oil, I can't track this down locally, presumably it needs to be an old classic spec oil without all the fancy additives... can you use staight classic SAE30 engine oil which I can get easily locally or is there anything else that would be ok? I seem to remember there were several oils specified over the years, are all the pumps the same even though alternative oils were specified by Merc

I have found diesel engine oil SAE20 on the web but it's expensive with shipping and maybe, being for a diesel full of additives, I would much rather get something locally

Cheers guys

[Alacrity]

I would have thought SAE 30 would have been OK given we only use our boats in the warmer months of the year. I can't see a real reason why you couldn't use auto tranny fluid in them. Se7en may have more input on this one.

[se7en]

On the last of the tilt'n'trims, with the pump in the boat, the type you and I have, they changed the decal, it says " SAE 20--40" there is no difference in the pump.
I have GTX in 'JADE's' pump, which I think is 10-40 , that's been O.K. for the last three years, as long as you drain all the old oil out, put in a mult grade engine oil, don't put a hydrolic oil in , that's to thin, if the tilt 'creeps' thats not the oil, thats muck in the valve block, the valve block sits in the bottom of the oil tank, all the muck goes to the bottom of the tank and cloggs the valve seats, give the tank a clean before you install it...............and if you write in crayon in your best hand writting............. 'Use SAE 20-40 in this pump' on the side.......you will have 'upgraded' the pump....just like mercury's did !!

[Alacrity]

See told you. The oracle hath spoken, so be it.

[Healey75]

Thank you oh wise ones....