Yanmar 3YM20 engine oil

[Plomong]

What brand and type of engine oil do forumites use for their Yanmar 3YM20 engines?

The problem arises because the boats dealer has recommended Volvo Penta 15W40 VDS-2, but that is an API CG-4 oil specifically prohibited by the Yanmar manual. As a result, I'm totally at a loss as to which oil to use.

Please help.

 

[vyv_cox]

I use any oil from a good manufacturer to API CD or CF-4 in my 3GM30. In UK it is difficult to buy to API CD, which has been obsolete for 10 years. In France it is relatively easy to buy Shell to this specification in many hyper-markets.

I think you are right to be careful. My reference for CG-4 says:

Introduced in 1995. For severe duty, high-speed, four-stroke engines using fuel with less than
0.5% weight sulfur. CG-4 oils are required for engines meeting 1994 emission standards.
Can be used in place of CD, CE, and CF-4 oils.

I don't think that the typical operation of marine engines, i.e. tending to be used for short periods, not at highest power outputs, relatively low temperatures, would qualify under this description.