GT so it's safe to say that 225ish would be ideal.
It's a little more convoluted than that.
250°F being the max, doesn't necessarily mean run it at 250°F, it means for short bursts, 250 is totally acceptable.
You want to be above 200 for the simple reason that the warmer temperature will boil out harmful water, this reduces the formation of rust (affectionately called iron oxide).
So if I had to pick a perfect temperature out of a hat, I would hope to pick 215°F
No water and long oil life.
This assumes the correct weight oil was chosen from the get.
The colder the oil, the lower viscosity number should be chosen.
Being as a multi viscosity oil has a 212°F spread from hot to cold, a multi-vis oil is not really necessary in our stuff, as an estimated example, if you boat at 95°F air temperature and use 20W-50 oil, the temperature spread drops to 117°F, if you are still with me, the oil is really closer to 35W-50, but has bunch of polymers to modify the final viscosity that aren't being utilized and reduce oil effectiveness.
Just food for thought.
GT
