1993 Johnson 30 lower unit oil question

[Dirkmaximus]

Hi,

We just bought a pontoon with a 1993 Johnson 30. Just wondering what gear oil I can use other than the Omc brand and if I need to change any crush rings or o rings when doing so. I have very little access to dealerships. Any advice would be greatly appreciated! Thanks!

 

[thdrduck]

I use a good 80w 90w hypoid lube. There should be a plastic seal on the screws, I've seen them stay in the unit and seen them on the screw, just want to make sure they are still there.

 

[AEROCOOK]

Fill with marine grade gear oil. It is preferred to replace the drain and vent screw gaskets though I've reused them in the past if they were still in good shape and never had an issue. Best to buy several of them and keep them on hand as they aren't very expensive. Go to YouTube for instructions, same procedure for practically every outboard regardless of make or model.

 

[lindy46]

Walmart or Tractor Supply has the 80w-90 marine gear lube - most likely cheaper than at a dealer.

 

[thdrduck]

So what is the difference between GL-5 Hypoid gear oil and "Marine" lower unit oil, other than price and the fact one says "marine" on it?

 

[oldboat1]

If new to the motor, and particularly if also new to boating, would just stick with brand names and identified "marine" products. The price difference isn't finally that great.

 

[flyingscott]

Hello here is the difference between marine and non marine gear lube. The marine gearlube is designed to still work if you have some water intrusion extra addditives for that. Standard lube for cars do not have those since your car is not components are not expected to run submerged. Stay with any good brand that is designated marine use.

 

[Dirkmaximus]

Hi,

Thank you all for the advice. Ended up going with Sierra marine synthetic blend gear lube as it's available in our small town and was suggested by the marina there. Low and behold, dropped the oil and it seems to be the exact same as what was in there, same colour and texture even though I bought the boat 350km away. No milkyness or moisture to speak of! None that I can tell with my limited experience anyway. Price was $17.99 Cdn for a quart, so a few bucks cheaper than some of the other "marine" lubes available at Canadian tire or Walmart. And thanks for the extra heads up aerocook, gaskets replaced with plastic rings/washers, there didn't seem to be a gasket or ring on the drain plug, and a rubber one sort of built right on to the vent screw. The plastic washers seemed to fit perfectly and compressed a little when tightening. Hopefully that works as intended! It seemed to make a good seal and I have no leaks out of the water anyway.