We used to use an Evinrude 6 hp 2-stroke as a trolling motor. It was two cylinders. It was light, smooth running, smoky, smelly, and polluting.
We replaced it the other year with a Yamaha 6 hp 4-stroke. The only downside with this motor is that we didn't make the switch years ago. Quiet, remarkably smooth for a single-cylinder engine, no smoke, no smell, no dumping half its fuel into the water with the exhaust.
2-strokes were fine in their day, but the sun has long since set on their day. I, for one, am glad to see the back of them. We have one more to change, the 90 hp Yamaha 2-stroke, 3-cylinder on our fishing boat. I'm looking forward to the day we can toss that one in the dumptster, too.