Evinrude 3.3hp 2 stroke gearbox oil

[Peter]

Got a approx 10, up to 12 year old Evinrude 3.3hp 2 stroke outboard. Works ok but need a to change the gearbox oil. Have no manual so need any know what grade oil to use in the gearbox.

Thanks

Peter

 

[VicS]

Any outboard gear box oil with a viscosity of around 80W-90.
Quicksiver is a readily available brand

Automotive oil is not recommended as it does not contain the emulsifiers and corrosion inhibitors which would give some protection in the event of water ingress.

Drain the old oil and inspect it. If it is of a milky appearance or if there is any free water it means water is entering the box and the seals require replacing.

Fill via the bottom hole using oil in a squeezable bottle with a spout that can be stuffed into the hole. When oil flows from the top ( level) hole fit the plug, then remove the oil bottle and fit the drain plug.

It is always recommended that new washers are fitted on the drain and level plugs.
Usually flat nylon washers on Johnson & Evinrude engines although some models do have plugs designed to accept "O" rings sometime even one of each on the same engine! Yours should be the flat nylon washers.

Post the model number and we can look up the exact year for you.

3.3 hp models appear to have been made 1991 to 1999 and again in 2001

 

[charles_reed]

SAE 90EP does the job just great - as Vic says you need an oil which can stand emulsifying and the EP additive does just that - it's easier (and probably cheaper) to obtain than marine leg oil.

 

[VicS]

SAE 90EP does the job just great - as Vic says you need an oil which can stand emulsifying and the EP additive does just that - it's easier (and probably cheaper) to obtain than marine leg oil.

I have no idea if the EP additives act as emulsifiers but it is not their purpose. They are additives in oils used in things like vehicle back axles with hypoid gears, where there is a sliding contact between the gear faces.

There is little call for the oils in back axles to emulsify water

I am lead to believe that outboard gear oils contain additional emulsifiers because there is a high chance that water will enter.

Outboard gear oils also contain corrosion inhibitors to protect the gears from corrosion in the event of water ingress

You may use an automotive gear oil, thats your prerogative but the only sound advice you can give anyone asking what oil he should use is to tell him the correct oil.

If he chooses to ignore that advice to save a few shillings each year that is up to him. There is no problem getting the right oil.