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1956 30hp johnson lower unit oil

wen4222

Member
"what is the difference in hyp

"what is the difference in hypoid oil and regular premium oil, does it have to say hypoid for it to be hypoid. Also I have 70 hp evinrude 1977 and was wandering what kind of oil I should use in lower unit on it."
 
My understnding is as follows

My understnding is as follows

Outboard gears are not actually the type of spiral bevel gears that are known as "hypoid" That type of gear is subject to some sliding of the gear teeth faces so the oils used contain Extreme pressure (EP) additives. A Hypoid or EP type of oil is not therefore really necessary.

I guess that in 1956 there were no oils specially formulated for outboards and that what were readily available were the EP oils for hypoid gears in vehicle rear axles.

You should therefore be using an outboard gear oil probably SAE 85 or 90 viscosity which will contain corrosion inhibitors to counteract the effects of small amounts of water ingress (or so they tell us!)

Electric shift outboards require a lower viscosity oil known as "type C"

I confess personally to using an automotive EP90 oil in a small outboard.
 
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