High performance or Premium Gear Oil.

[UKGlenn]

Hi. I have been following SO annual service who asks for High performance gear oil but I went and bought Premium Gear oil as it is in the Mercury specs.
What do you use?
Thanks.

 

[UKGlenn]

Hi. I have been following Sj's annual service who asks for High performance gear oil but I went and bought Premium Gear oil as it is in the Mercury specs.
What do you use? Does it matter if I've taken High out and put premium in?
Thanks.

 

[Djs]

I use a high quality 80/90 and change it every year.

 

[Dr Honda]

The Merc spec for the Sportjet is the High Performance. (not the premium) You can use what you want... and I generally don't push a particular oil over another... but the Mercury oil will keep any water that gets past the seals in suspension better than a regular gear oil. AND... the "Premium" oil doesn't have the shear strength that the sportjet needs.

SO... with the engine oil... I say "Any good TC-w3". For the Rotax... I say... "any good API-tc oil"... but in this case... I haven't found anything equivalent to the "Premium". Yes, it's expensive... but you only need a little more than a quart... so it's not a big deal to buy the right thing.