The outboard oil thing.
Theres oil for water cooled.
And oil for air cooled.
For motorbikes it does not seem to matter too much which cooling its more a specified motorbike oil.
But for water cooled outboards the oil is a different formulation. I would say to do with the cooler cylinder temps and the fact that the burnt oil is exhausted through the water.
The bit i find difficult to get my head around with the Victa reccomended 50:1 oil is the jetting effect.
Oil takes up volume in the fuel. The fuel is metered. The oil is not the volatile combustable. If you have less oil in the mix you have more fuel flowing through the jet. If you have more oil you have less fuel.
Rich is cool. Lean is hot.
To burn the oil off you need optimum temperature and burn etc or you get smoke.
So i find it hard to accept that through oil formulation alone you can get an oil to lubricate the internals and burn off without smoking in an engine that is running cooler.
Its naught to do with the pre mix ratio, its everything to do with the jetting.
A low stress 160cc two stroke that spins at less than 4000rpm could easily be run on 100:1 mix with no ill effects caused by lack of lubrication.
Folk law has it that with a 125cc dirt bike its safe if you dont go less than 32:1 and they will wail well over 10000rpm.
