Four-stroke oil question

[GregE]

What are the differences in four-stroke oil versus regular automotive oil of the same weight? (other than price, which is a huge difference)

Such as 10W-30 4-stroke oil vs 10W-30 automotive oil?

 

[Bigjohn1]

Re: Four-stroke oil question

The difference is the FCW certification that marine oils have. It is said they have more corrosion inhibitors than automotive oils. Personally, I could care less and run brand name 10W40 non-syntheitc in my 4-stroke outboard. 600 hours, 4 years, and still running strong.

 

[Chris1956]

Re: Four-stroke oil question

Greg, 4 cycle marine engines operate under much more average load than automobiles, due to constant water resistance. A way to think about it is to say that a boat motor always has a load like a car always going uphill, against the wind.

MerCruiser made a non-synthetic 25-40 motor oil for their sterndrives. They recommended either their 25-40 or a straight weight automotive oil. It was thought that the automobile multivis oils (10W-30, etc) simply did not provide enough lubrication under the demanding load of the sterndrive motor. I would think the same is true for the 4 cycle outboards as well.

The bottom line, use what the manufacturer recommends, or take your chances on engine damage. Your motor is not the same as a car engine.

 

[GregE]

Re: Four-stroke oil question

Thanks all. It was a curiousity and the price difference is rather significant. But anything with the word "marine" on it always is.

 

[Cricket Too]

Re: Four-stroke oil question

Greg, 4 stroke outboards tend to "make" oil more than 4 strokes in cars, since they run a lot cooler. The marine motor oil is supposed to handle this extra moisture that accumulates in the oil better.

 

[gss036]

Re: Four-stroke oil question

Cricketto, I agree w/your statement about making oil, but! where did you get your info on the oil. That is the fist I have such a statement made. Would you mind sharing all this info with the rest of us.