PWC (jet ski) onboard storage and maintenance

Personal watercraft (Sea-Doo, Yamaha WaveRunner, Kawasaki Jet Ski) on yachts are typically stored on a hydraulic swim platform, on chocks lashed to the deck, or on a garage door. Weight range: 500-1050 lb depending on model. Storage rules: (1) Chocks and straps rated for the weight. Ratchet straps at four points, never bungee cords. (2) Fuel: never leave a full tank when unused for more than 30 days without stabilizer (Star Tron or Sea Foam), ethanol phase-separates in coastal humidity, gumming carbs and injectors. (3) Battery: pull the negative terminal or install a battery maintainer if plugged into shore power. Deep cycling a PWC battery below 12V kills it in a season. (4) Cooling flush: after every salt-water use, flush with fresh water via the flush port for 90 seconds AT IDLE (never rev the engine while flushing, impeller cavitates with air). Maintenance intervals: (a) Every 50 hours or annually: oil and filter (4-stroke), impeller inspection, spark plugs. (b) Every 100 hours: intake grate inspection (bent grates = cracked hull from grounding), driveline oil change, cable inspection. (c) Every 200 hours: valve adjustment, propshaft seal service. (d) Winter storage: fog the engine, drain cooling passages (mission critical, a frozen PWC engine cracks the block, unrepairable), lift the front to drain hull water, cover with a breathable cover. Common failure: sucking a rope, plastic bag, or seaweed into the intake, jams the impeller and can crack the pump housing. Kill switch immediately, inspect and clear before restarting.