Originally Posted by codprawn
It is a good point about development costs - the majority of 4 stroke outboards have other applications. The new yam 350 is based on a Ford V8 car engine.
I think there's been a lot more research and testing on 4-strokes, due primarily to the larger market share they enjoy.
A few years back, there was some experimenting done with a 2-stroke engine that used sumped lubricating oil and ran on pure gas. Not sure why that didn't go further than it apparently did.
As to oil going into the water a lot depends on the oil and the ratio - remember eventually a 4 stroke's oil will also end up back in the environment - especially if someone just chucks it away.
That's sort of like saying that a wood bridge is a better alternative to steel because eventually someone will toss the steel on the side of the highway. If you assume the oil is going to be recycled (and ideally, many times), well, yes, it will still end up in the environment, but only after many, many cycles of uses. A 2-stroke engines oil gets into the environment after a single use.
Speaking of which, I think my oil storage bucket is full, and today would be a good day to take it to the recyclers for emptying.