I have a 90 HP Mercury 4 Stroke that I would like to do an oil change on... My problem is i have heard different opinions from several people. I will run the boat till freeze up (Walleye Fishing). Some say run any brand 10W30 cause of the cold temperature while others say run Mercuy 25W40 synthetic blend but wonder if thats too thick for cold temperatures. I am not sure and looking for the right oil as I don't want to wreck any bearings as well as the motor is under warranty still as i bought it new this passed fall.
thanks in advance
thanks in advance