Currently using m1 15/50. Someone on a thread don't use a SM rated oil as the M1 is. Motor runs good but burns oil.
In another thread they said use only 40. Does anyone have the hull truth?
Thank u so much.

How much oil??? 502mpi's all use oil due to the stock low tension rings.
A quart every 8-15 hrs is pretty normal.

At least that. I saw on a thread don't use SM based oil. Whatever that means thanks for the reply.

Sounds a lot like mine only you might be using less oil. I could go through a quart in 3-4 hrs. Changing oils didn't make much difference. Changing pistons and rings seems to have solved the problem completely.

Mine went thru mobile 1 like crazy... Went back to straight 50w valvoline VR1 & made a very noticeable difference FWIW!