type of oil to use in the lower unit

[manitoba1]

I'm replacing the oil in the lower unit of my Suzuki DF70 4 stroke and had a question regarding the type of oil to use. The manufacturer recomended a 90 weight single viscosity oil marine lubricant. I been told by some that a good qualilty differential oil like a 80w90 should do the trick. Just wanted to get some expert opinion on the subject. The oil sold by marine manufacturers are substantially more expensive and wanted to know if I'm paying for an actual superior product or just the name.

 

[tashasdaddy]

Re: type of oil to use in the lower unit

walmart sells the same thing 90# outboard gear oil.

 

[cobra 3.0]

Re: type of oil to use in the lower unit

Marine oils, especially synthetic, seem to do better if there is water intrusion...or so I have heard.

 

[Paul Moir]

Re: type of oil to use in the lower unit

Outboard gearcase oils invariably contain emulsifiers which help the oil cope with water ingress and prevent corrosion of the gears, bearings, etc. Differential oils usually don't. BRP Ultra-HPF for example claims it'll lubricate a gearcase fine when mixed 20% with water.

I use a lot of Motomaster (Canadian Tire) "Formula 1" premium 90w outboard gearcase lube. It's relatively inexpensive and works very well. Princess Auto carries a cheap gearcase pump with a metric adapter for your Suzuki, <$10. Ultra-HPF is superior but more money.

EDIT: There's no question with that water intrusion business. I use my old gearcase lube for drilling, tapping and machining. Mixed with some water (which l/u oil does easily), it makes a good tool coolant.

 

[kenmyfam]

Re: type of oil to use in the lower unit

I spend the extra few bucks to be sure. If I am wasting money by doing this then at least its not too much !!

 

[manitoba1]

Re: type of oil to use in the lower unit

Appreciate the input. Picked up some premium outboard 90w gearcase lube from Canadian tire today and changed it up. Old oil was as clear as new but it was due for a change.

 

[Paul Moir]

Re: type of oil to use in the lower unit

It's always good to know you've got a gearcase full of oil rather than water when the mercury drops below zero.