What the mechanic means by 10 years old or newer is a 4 stroke. Modern day 4 strokes can go 1000s of hours, which was unheard of in the 90s. $1,500 will not by any four stroke jet ski, you're looking at about $4,000 minimum (prices are regional and I'm assuming he needs a trailer too).
mid to late 90s yamaha 2 stroke jet skis are very reliable (by two stroke standards), the 760 is said to be one of the most reliable two stoke jet ski motors ever made. If you want a jet ski for under $1,500 that you don't have to do anything to and will most likely start every time you put it in the water this is the route to go.
The seadoo 787 motor is IMO one of the best motors ever made and I have two skis with them. They are notorious for problems but if you address the weak spots up front and take care of them they can be very reliable. The biggest weak point is that the original fuel lines will cause the engine to seize (sounds crazy I know). Today's ethanol degrades the line and clogs the carburetor. Those must be changed and carbs cleaned out. Another weak spot on older seadoos is the computer, jump starting or trying to start it with a battery charger will cause the computer to blow and they are not cheap. My mint condition '97 SPX that I love left my son and I stranded in the middle of the lake once when the computer blew for no apparent reason - I'm guessing someone before me jumped the battery.
Thank you for your input, I think you brought up a point that I am now realizing it seems like the power plant is more important than the jetski and mentioning the weakest link. I could only find 4 jetskis in a 100 miles that had 4 strokes and a trailer. They were between $3,500 and $3,800. I saw this one and apparently the 4 stroke is bullet proof:
http://buffalo.craigslist.org/boa/5046973776.html
I also hear to avoid the super charged 4 strokes as the SeaDoo's super chargers require frequent rebuilds ~100 hours. So I guess in all naturally aspirated modern 4-strokes are the best. He started talking about spending more, though I am not sure how much he is willing to spend. I think he wants a water craft in general. Though he doesn't mind taking a risk on the ~$1500 range then getting something better further on. Though I hope he doesn't get totally put off by the sport, if he gets a lemon. In any case it seems like the in this price range the PWC, doesn't go down in price, unless it is broken.
I also hear a lot of people convert their jetskis into premix as the pumps can fail as well.
In all here is what I am gathering from my research:
2-Strokes:
Easier to work on
Require more maintenance
Will cost less for each fix, though more in the long run
Louder
Smelly
Waste a lot of unburnt gas and oil, up to 4Gal/hour in tests
Less Reliable
Cheaper up front
More power to weight ratio
Can/Is banned on some water ways
4-Strokes:
Most reliable w/ naturally aspirated
Will cost more when repairs are needed, but less in the long run
Some engines are referred to as bullet proof compared to 2-strokes
Much better on Gas/MPG/MPH
Heavier
More expensive up front.
Will retain higher resale value than 2-strokes
