When buying a used Yamaha jet ski, avoid buying a two-stroke jet ski, disregard engine hours, test the jet ski on water, and check the entire jet ski for damages. Take the price into consideration as well. Since some brand new jet skis, such as the Seadoo Spark, are available with a warranty for the price of a used jet ski, consider buying a brand new one instead.
Jet skis that have two-stroke engines are being taken off the market because they produce much more pollution than jet skis with four-stroke engines. That also means replacement parts for 2-stroke engines have become harder to find, giving the buyer more trouble if his jet ski encounters engine problems, as shops are less likely to work on two-stroke engines.
Don't base your decision on engine hours, since maintenance and hull condition are more important factors in a jet ski's life span. Never buy a second-hand jet ski without water-testing it first to make sure that the watercraft takes off instantly.
Check the entire jet ski for damages before purchasing it. Check for tearing on the seats, fiberglass damage on the bottom of the ski and missing parts from the watercraft. Check for rust as well, especially around the engine and the pump. Engine paint chipping off is usually a sign that rust is about to become an issue.