IMO the choice between 2 cycle and 4 cycle Outboards is more complicated than number of cycles. Carborated 2 cycle outboards are a different animal than either 4 cycle or 2 cycle direct injected outboards.
4 cycle outboards have been perfected. 2 cycle direct injection outboards like Optimax and e-TEC have also been perfected. The difference in price, fuel economy and maintenance between new 4 cycle and 2 cycle direct injection OBs is minimal. For a new motor, I would choose either.
If buying a used outboard, and price is the driving factor, a carb'd 2 cycle motor will be the cheapest, but cannot be used on some bodies of water. It will cost far less than a new OB, but use more fuel. Maintenance costs is far less as well.
IMO, with normal seasonal use, a carb'd 2 cycle OB will not use enough extra fuel + oil to make up for the difference in price compared to a new outboard. So if you choose to buy a newer 4 cycle or 2 cycle DI motor, you are doing that for the dependability of a new motor, and ease of servicing.
