Force motors are awful. Outboards are one item that you truly get what you pay for. Force motors are totally unreliable. Wonder why you don't see Force motors on big bass boats?
If you are looking at older boats, OMC motors like Johnson and Evinrude were very good. I don't know about the newer ones since they were bought by Bombardier. Having owned several boats in the last 12 years, my favorite is a Yamaha. I'll share a few tips that a good friend gave me before I bought my first boat.
1) Look at the underside of the hull and pay close attention to the lower unit/prop on the motor. If these areas are full of big dents and deep gouges, the owner has been pretty rough on the boat. Of course you have to expect minor scratches on the underside of the hull through normal use. The lower unit is the most important. If the part of the motor below the prop has significant gouges or dents, it is a sign that the owner ran into something. It's just a matter of time until the lower unit goes out completely.
2)Ask the owner how they stored the boat when not in use. Anytime a boat is being stored more than about 30 days, the gas line should be disconnected and the motor ran until all the gas in the carb has been used. Since all 2 stroke engines take gas/oil mix, it really tends to gum up the carbs. The owner should also have used fuel stabilizer if the gas was in the tank longer than 30 days. Not many folks do this, but they should.
3)You can also ask about greasing the bearings in the trailer. Most people neglect this. Since the wheels of the trailer are consistently submerged in water, it is paramount that the bearings stay packed with fresh clean grease. Several fishermen have found this out the hard way by dropping a trailer wheel. This tends to do some boat damage.
4)Last thing, look at the capacity plate. This is the plate that tells you how many people you can have on board and how much horsepower the boat is rated for. Boats are required to have them. Most boat dealers put undersized motors on their boats. This is a selling tactic, it makes them look more affordable. If you have a boat rated for a 115 HP motor and it has a 60 HP engine, it will be real sluggish. If it's rated for a 90 and it has a 75, there won't be a huge difference in performance.