1978 Mercury Lower Unit Oil Weight

[minnguy32]

Im changing the lower unit oil on my 1978 mercury M800 80HP...the book says to use 85w-90 oil...im seeing 80w-90 and my local shop...is there much of a difference? can i use 80w-90? any help would be great...thanks alot

 

[Bondo]

Re: 1978 Mercury Lower Unit Oil Weight

Im changing the lower unit oil on my 1978 mercury M800 80HP...the book says to use 85w-90 oil...im seeing 80w-90 and my local shop...is there much of a difference? can i use 80w-90? any help would be great...thanks alot

Ayuh,.... You Can, but the newer syn-oils are Much Better,...

I use Mobil 1, 75W-90,....