accidently put gear case oil in engine oil

[chrisnowak25]

I have a 50hp outboard that I put gear case oil in the engine oil compartment. There was 10w30 in the compartment and only added about a 1/4 of a bottle before realizing. Will this cause an issue? If so, what do I need to do?

 

[bruceb58]

This is a 4 stroke I assume?

I wouldn't worry about it.

 

[Alumarine]

For the cost of new oil and filter I would drain it.
It might not do any harm but it's sure not doing any good.

 

[bruceb58]

Just so you know, 75 gear oil is about the same viscosity as 30 engine oil. You only put 4oz of it in your crankcase so not to worry. You are way better off than if you had put some of the oil additives that do nothing in there.

 

[hondam]

Personally i wouldnt even question it, give it another oil change. Honestly i have no idea if it would do any damage or not, heck even if it probably would hurt anything. Probably isnt good enough when you consider materials for an oil change are less than $25 and a new 50hp outboard is in the $7000 range.

But that might just be me, type A and big believer in doing it right the first time.

Also in 4 stroke outboards should be using an FCW rated oil. It is specially formulated for marine environment and outboards. It has an additive package that reduces aeration and foaming of the higher revving up-righted engines and better corrosion resistance.