Re: oil weight
Why diesel oil? Are the additives that much better than marine oil?
It usta be that Diesel oils had an older style additive package, similar to what was available in gasoline oils around the time your engine was born. Those additive packages had high pressure lubrication additives that are good for flat tappet lifters.
Most modern diesel oils are becoming more like regular gasoline oils. They are removing some of the old school additives, because modern diesels are now using diesel particulate filters in the exhaust system. Some of the heavy metals present in the older style oils will eventually poison those filters, hence their removal.
So...
Run what Mercruiser recommends, or what ever you feel like...
