Boats are throw away items... motors are not. If you are looking at pontoon boats (presumably for lake and river use)... check the welds around the endcaps of the pontoons theirselves... and if it is a seamed pontoon, check for cracked weld there as well. Fiberglass hulled boats such as cabin cruisers orbass boats, or center consoles, check for cracking and deep dings where the fibers themselves could be exposed. Also check for signs that the boat has been holding large quantities of water. Typically the only rotting fiberglass boats experience is where there is wooden braces... such as motor mounting areas. Back to the motor... this is the most expensive part of a boat, really if the motor is no good, the boat is no good. Check for oil leaks and make sure it starts and runs well. Stay away from engine brands like Force... brands like Mercury, Evinrude, Honda, Yamaha ect. are quality brands you would be ok with for out boards. If you find something you like, get as much info as you can and research it. Remember, the best two days of a boat owners life is the day he buys it, and the day he sells it!