Gear case oils

[Mc Tool]

Time has come to fill my reconned gear case with oil . I have long used synthetic gear oils in my bikes and cars , and used ATF in my racebike gearboxes . I like the thin oil , convinced that it soaks up less power.
Have any of you used synthetic gear oil in your outboards ? opinions ?

 

[airshot]

Time has come to fill my reconned gear case with oil . I have long used synthetic gear oils in my bikes and cars , and used ATF in my racebike gearboxes . I like the thin oil , convinced that it soaks up less power.
Have any of you used synthetic gear oil in your outboards ? opinions ?

Yes....used it for years in my small outboard motors and never had an issue.
These motors never worked hard, so if this motor will be run hard or is a larger main engine, I would follow mfgr recommendations !

 

[Mc Tool]

Its an 18hp Tohatsu 2/ that will be on a 3.8m inflatable

 

[airshot]

Its an 18hp Tohatsu 2/ that will be on a 3.8m inflatable

The stuff I used was Marine grade syn. 75w gear oil. Bought mine at Walley World, our stores get their oil products from Valvoline. Depending on where you are, those products could be made by other companies. If you motor is under warranty, I would wait until out of warranty. Have used this stuff for many years with no issues. My current little kicker motor has been using it for 5 years and the prior kicker motor used it for ten years with no issues. Your call.......