A 2002 would be just after Bombardier took over from OMC. In 1997, OMC released the FICHT fuel injection system into some of their motors, which ended up being the final straw that broke OMC's back. The OMC carburetor motors of the 90's while thirsty, are very reliable. FICHT motors are to be avoided like the plague. The Bombardier motors (2002 +) are said to be be solid, reliable motors.
Checking compression is very easy and testers are cheap (YouTube is your friend). Certainly something you can handle on your own. The important thing is consistent, acceptable compression in all cylinders. Take off the cover and look over the motor closely. Look for discoloration, melted wires, warped plastic, etc. Basically look for any signs of overheating. Other than that, I would hear it start and run (on muffs of course) and I would crack the lower unit screw to ensure the lower unit oil is a nice dark blue. While it could have just been changed and you still may have a leak, don't underestimate how lazy people are. If it is milky gray, assume a $600 - $700 lower unit rebuild on that motor. If you can dump it in somewhere and take if for a test drive/ride, all the better.
Finally, I would check what the boat is rated for for HP. Boats all have a plate somewhere on them that will state how many passengers and what HP they are rated for. I would make sure 150 HP is at least 85% of what the boat is rated for. If it is less than that, you will likely be under powered and dissatisfied at some point. So, if the boat is rated for anything over a 175 HP, personally I would pass.