Yanmar Diesel Engine Oil In A 4 Stroke Outboard?

[rnbenton]

I found 2, one gallon jugs, of Yanmar Diesel Engine Oil, 15W-40, in my garage. My 4 stroke Yamaha 150 outboard is due for an oil change so I was wondering if this oil can be used. It was pretty expensive and I'd like to use it if possible but I certainly don't want to bugger my outboard.

It is labeled on the back "API Service CI-4, CI-4 Plus, CJ-4/SM" If that helps. Can I use it or no?

Bob

 

[pdecat]

Bob: Much of the new specs for spark and compression ignition seem to be focused on reduced emissions, soot control, not plugging catalytic converters, reducing scuffing and start up wear. None of those things tell me that the oil is not good as a lubricant.
Personally I would use it because engines never seem to fail prematurely due to lubrication issues.

http://www.apicj-4.org/2009_ENGINE_OIL_GUIDE.pdf

 

[Capt. Bill1]

What Bruce said.

 

[smitty477]

IMO - it is fine for the ratings but I always used 10-30 weight oil in my F150 Yamahas with good results. I would use the 15-40 in my pickup or find an alternate good match for its specific designed weight.

Hope this helps

 

[Sandy]

I would think your 4 stroke outboard specs API-rated "SM" oil as perfectly fine, as long as it is the correct weight. I would not hesitate to use it in the Yamaha crankcase.

FWIW- I use Valvoline diesel oil in my Crusader gas I/B's all the time since it also has the most recent "S"-rating for spark ignition engines.