‘98 9.9 Evinrude 4stroke oil?

[Rabbit929]

I’m new here with an old ‘toon, with this motor on it.
I’m wondering what kind of oil y’all run in the motor?
Are you specific to marine brand name oil or does it really make a difference to our regular full synthetic quality oils in?

Some people are motor brand specific, or amsoil, ect.
I’m just wondering if general 5w-30 automotive oil will work just fine or not.

[lakerunner]

I have to run specific oil in my E-Tec as it is set at 100/1. Otherwise I would use good 2 stroke oil by other makers

[Rabbit929]

That’s the thing, mines a 4 stroke.
I’m just wondering if I can use regular 5w-30 or if it has to be marine oil.
Also any recommendations for the lower unit?

[Steiner]

Marine oil has added rust inhibitors and is designed to not thin like auto oil can at high RPM maintaining viscosity and resisting shear. A boat motor is often tasked with turning 4-5000 RPM for long periods and runs at a cooler temperature than an auto so there are different additives needed for wear protection as auto oils have some that need to be at higher temperature to activate.

Would you ever notice a difference outside disassembly and in a lab? Maybe not but given marine oil is readily available at even Walmart there's not really a good reason to not use it. Same goes for the lower unit. You'll most likely need a pump with correct adapter to fill it from the drain hole.

As far as brand, it's tough to go wrong with the lubricants branded the same as your engine. I use partsvu and just order their manufacturer specific 100 hour kit but I think they just do kits for Mercury and Yamaha. They carrier some Johnson parts, lubes, and Sierrra marine lubes certified for all brands though.

[lakerunner]

Sorry I missed 4 stroke. When I had a 4 stroke after warranty I ran regular oil.