Sorry guys, meant to post this in "off topic"
In addition to mopeds and some other stuff, I also have a boat and two motors for it, one I use for smaller lakes and one I use for bigger lakes. I was fishing this weekend and thinking about powering a moped with a two stroke outboard.
Here is my thought process: The ones that are small (6 hp and under) are small enough and light enough to be a possibility, especially without the transom, prop, cover and everything. 6 hp would probably be too much, but a 4 or less might work with reasonable structural help on a moped frame. They are also essentially one speed transmissions anyway, just like a moped.
Would it require a clutch and variator? I think most of the gear shifts in outboards is in the transom so if it was just a gear on the output connected to a chain, as soon as it was running, it'd be moving, unless you started it with the wheel off the ground, and dropping a spinning tire with no clutch might be a questionable start, even at idle.
Another thing I thought about was that most outboards are water cooled through the transom, which would be a problem. Maybe there are some air cooled outboards?
Has it been done? Aside from the impracticality and cost of it, does it seem accomplishable? What are your thoughts? (edited)