When you are dealing with a 13 year old boat... there really isn't any specific thing to look for.
The 240 EFI is a good engine, but depending on how it's been cared for, and how much time is on the clock... it could be nearing the end of it's life. But, there is a good chance that it's already been rebuilt/replaced. (that's a question to ask)
If it hasn't been rebuilt yet, and runs well... you will want to consider removing the oil injection, and mixing the fuel with oil. The issue is... the main drive gear is plastic, and it doesn't last forever. It is known to simply wear out, and that will kill the engine shortly after, from lack of oil. If the engine has been rebuilt, then it should be fine. The original gear will go +10 years... and the new style gear is stronger.
With any vehicle... you want a test drive. So... put it on the water, and take it out for a real ride. It's a EFI engine, so it will start cold quick. (just a couple seconds of cranking) The 240 EFI is VERY smokey when cold... so that shouldn't be a concern... but it should clear up after a minute or so.
Run it at a higher throttle setting (+70% power) for 10~15 min. Make sure there isn't any over heating issues. Then shut it off, and sit for another 10 min or so. Then, restart. You will need to use the bilge blower, but it should restart easy. Also... while out on the ride... it should idle smooth, and accelerate, without cavitation.
If the owner won't let you take it out on the water... just pass on it. (unless it's cheap enough, that you don't mind fixing things) One thing to keep in mind, is even a crappy engine will run without a load on it.
Other than that... turn on all the switches, and make sure things work. Make sure the steering, throttle, and shift lever are smooth, and not tight.
Good luck with the buy.
