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I've seen tiny outriggers used for fishing,etc that are two-stroke. Maybe some jet skis too? I'm not sure.

Certainly anything substantial won't be two-stroke.

As I understand it, there are increasing restrictions and calls to ban 2-stroke marine engines for smaller lakes, because the exhaust contains a fair amount of oil mist that settles on the water.

If nothing else, the noise is a nuisance on small lakes. I grew up next to a small community-governed lake on which all gas was banned. People have been using electric on that lake for ages, which is particularly feasible since it's a small lake (300 acres or so iirc). Electric for small stuff makes a ton of sense and has for a long time.

My parents-in-law also live by a lake where all ICE's are banned. Mostly people row, and a few have electric outboards.

It's really wonderfully quiet, even though it's close to a city.

Besides the oil, the carbureted 2-strokes emit 25%+ of their fuel unburned.

A long time I read about some "next generation" 2-stroke thing, where they had fuel injected directly into the cylinders, after the piston had already blocked the exhaust port. The intake port was only used for air. A bit like those behemoth 2-stroke marine diesel engines.

Evidently it didn't really work out well enough, considering most outboards they sell these days are 4-stroke. I've always had a soft spot for 2-stroke engines, seems so wasteful to "waste" half of the strokes on a 4-stroke. Oh well.

Evinrude's E-Tec line is two-stroke and goes up to 150 horsepower in the G1 series, and to 300 horsepower in the recent G2. That's pretty substantial.

OTOH, they have done a lot of engineering to meet emissions requirements, so they are a far cry from grandpa's old outboard that left trails of blue smoke.

The E-Tecs have done exactly what you said - a lot of engineering to meet emissions requirements. Unfortunately, the requirements for outboards include CO, NOx, and HC, but not P2.5 or P10 (particulate) emissions, because they are much simpler and less scrutinized than the regulations on cars (which DO have particulate limits). The E-Tecs put out 30X as much particulate emissions as the 4-strokes.

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