There are lots of 2 cycle engines available now at
www.craigslist.com.
I found a 2000 model 15 HP Tohatsu/Nissan for $900 with only 5 hours on
it. Tohatsu (92 lb.) is heavier than Yamaha and Mercs. Hard to check
specs on the other two because all 2 cycles specs are becoming archived
stuff on the company's web sites.
Boat: 1998 12' Prestige Conquest (Achilles) (wood floor, inflatable
keel, PVC, 16" tubes)