Re: Lower unit lube Yamaha 150
Any 80-90 Wt.Marine Lower Unit Lube will do fine, just drain whatever is in it and pump it full of the new oil. I use the Walmart brand which seems to work fine. Drain old oil into a clean container so you can inspect it for water, contamination, metal particles. There may be very fine metal particles on the lower drain plug magnet that are normal and do not indicate any problems. I've heard of old lower unit oil coming out very dark or black and smelling bad like sulfur, but mine always comes out looking just like when I put it in. I believe any water intrusion into the lower unit can create a milkyness or darkening of the oil and can create some big wear and corrosion problems. Good Luck!