I had an 05 Seadoo RXT, sold in fall 08 for boat. I did my own maintanance. I am pretty family on the basic stuff of the 4tec engine. Assuming you are looking at a newer model that has this engine. All based of the same base engine 3 cyl 1500 cc. Base engine starting at non-supercharged, then supercharged, then top end- supercharged & Intercooled.

The do require oil changes like any engine. Although they have a self contained cooling system, they should have some winterizing- the exhaust still used lake water for cooling just like our boats and its not self draining, stabil for the gas, disconect the battery. That cover most of the big times.

I believe around 04-05 was the big switch to the 4 stroke in seadoo. To test drive, like mentioned, check oil & gas, key and go. Thought most had a multi fuction LCD screen for speed, tach, water/air temps, hours, ect.

They can consume some fuel but also look how you would drive it, drive your moomba that way and it will drink gas.