Can I use Mobil 1 5W-50 SuperSync oil (100% synthyhetic) in Mercruiser GM
V-8 350CID (5.7 L) in 15 year old marine engine? The manual specifies
detergent 20W-40 or 20W-50 oils. What effect could have the 5W-50 viscosity
range (5W vis 20W)? The vessel is not used often, is stored on hard stand,
the winter temperatures are hardly below 10 degrees C and the engine is run
at least once every month for about 10-15 minutes.

Appeciate your thoughts
Mark Zak