It's pretty simple. 2 strokes are half the weight for a given horsepower and as the other gentleman mentioned you can store them however you wish on either side... granted the newer Yamahas you can lay down on either side but that is not true for most 4 strokes. so 30 to 50 lbs? yeah for a 4 HP... but you can get a 10 HP
2 stroke is the same weight range. Some of us who are
trailer sailors need the smaller engines for our dinghys and a 3.5 hp
2 stroke is around 20 lbs. Also, many of these manufacturers STILL MAKE 2 stroke motors... they just don't export them to the United States (that's how the fellow got one from
Malaysia. Also, my sailboat is rated to 20 HP but I can't even haul a 9.9 HP on my
boat without it negatively affecting the balance while it is on the
trailer to the point where it is dangerous (100 lbs) so I had to go with a 4 HP
motor (4 stroke) which is fine on lakes BUT in the Gulf 4 HP just don't get it in rough seas. If I need the bigger
motor I have to haul it in my truck. Hoisting 100 lbs on and off a sailboat motor mount is a 2 person job. My main point being that there are MANY VALID reasons to desire/use a 2 stroke or a 4 stroke motor. Also, the newer technology IS AS CLEAN AS a 4 stroke engine. There only persists a stigma because visions of clouds of smoke surrounding the older 2 stroke engines.
JMS