Mercury Force 90 Lower Unit Oil

[zheka]

Hello. I am trying to flush and replace the oil in the lower unit, but I can't seem to find the exact answer.

I came across PDF file from mercurymarine.dk that says to use "Quicksilver Premium Gear Lube 80W-90 For Outboard lower units below 75hp". (mines 90). Then towards the bottom, it says to use "Quicksilver Premium Gear Lube" for all Force engines.

The 2 statements seem to constrict each other, and I can't seem to confirm which oil to get, Premium or High Performance.

 

[haventaclue]

Either will do,I would use any generic lower unit lube as long as it meets the GL5 non frothing specs, others have different opinions.

 

[zheka]

Either will do,I would use any generic lower unit lube as long as it meets the GL5 non frothing specs, others have different opinions.

They have different viscosity. Premium is 80W-90, and High Performance is SAE 90. Am I still good to use either or? If so, would High Performance be better though?

In addition, I'm in Florida, and the lowest temperature in the gulf, is probably in the 50-60's, so the boat will never see anything colder than that.

 

[Texasmark]

Either one. They are interchangeable in the high temp side. Like 10W-30 vs 30W for engine oil in Florida.

 

[timguy]

Agreed, either would be fine. Warmer water, I prefer hp, that's what we run in the Philippines....ocean stays around 82 degrees in Davao Gulf.