Just for clarity, there's a big difference between older 2 strokes (carbureted or fuel injected) and the newer 2 stroke engines. Mercury uses a low pressure air injection in their Optimax engines (these are what the Marine Patrol runs on several of their patrol boats), Tohatsu has a similar LPDI system for some of their engines. Yamaha had several high pressure direct injected two stroke engines in production a few years ago, not sure if they still manufacture these. Evinrude E-Tec engines are all high pressure direct injected and are EPA 3 star rated for emissions which is equivalent to or better than ratings for 4 stroke engines (depending on size and manufacturer). The "new tech" 2 strokes are typically significantly lighter than the same HP engine in a 4 stroke. Weight can be a big factor especially when trying to repower an older boat so it's good that "new tech" 2 strokes are available.
Any of the newer 2 strokes mentioned above have almost zero smoke / odor, nothing like the old school engines. I had a Mercury 115 "tower of power' back in the day, on a cold start it looked like the boat was on fire!
