How to Buy a Used Jet Ski or PWC Without Buying Someone's Headache

Read the hours, then read the rider

Modern four-stroke PWC track engine hours in the ECU, and you can pull them up on the dash of most Sea-Doos and WaveRunners or with a dealer's diagnostic tool. Under 100 hours is genuinely low, 100–200 is normal for a well-used ski, and 300-plus isn't a dealbreaker if it was maintained — a flushed, garage-kept freshwater ski with 250 gentle hours will outlast a salt-thrashed one with 60. Older two-stroke skis (roughly pre-2010) burn oil and are cheaper to buy but harder to find parts and dealer service for; four-stroke Rotax, Yamaha, and Kawasaki engines are the safer long-term bet.

• Ask directly: freshwater or salt, flushed after every ride, stored indoors, and winterized each fall — and watch whether the answers come easily or get vague.
• Match the hours to the wear: a chewed-up seat, scuffed rub rails, and sun-faded graphics on a ski claiming 35 hours suggest the cluster or ECU that stores the hours was swapped, so treat the reading as unknown.
• A ski ridden hard and wide-open by teenagers wears very differently than one used to tow tubes on a calm lake — ask who rode it and how, not just how much.

Cold-start it and check compression

Insist on a cold start. A seller who runs the engine warm before you arrive may be hiding a hard-starting or smoking motor. Once it's running, listen for a steady idle and watch for excessive smoke or a rough note. Then do the one test that saves thousands: pull the spark plugs, thread a compression gauge into each cylinder, and crank the engine over a few times with the throttle held open.

You're looking for healthy numbers and, more importantly, even numbers across cylinders. Healthy four-strokes typically read well above 120 psi, but the exact figure matters far less than the spread. If one cylinder reads meaningfully lower than the rest — roughly 10% or more — you're likely looking at worn rings, a scored piston, or a bad head gasket, and on a supercharged ski a low cylinder can mean it detonated. A $30 gauge is the cheapest insurance you'll buy all day.

• Bring your own compression gauge and plug socket; don't rely on the seller's word or an 'it runs great' listing.
• Uneven compression is a walk-away or a heavy price renegotiation — top-end rebuilds on a PWC run well into four figures once labor is included.
• While the plugs are out, read them: oily, fuel-fouled, or one plug that looks nothing like the others is another clue something's off.

Put your hand in the pump — wear ring and impeller

A PWC makes thrust with a jet pump, and this is where sucked-up sand and rocks quietly cost the previous owner performance they may not even mention. With the engine off and the key and lanyard pulled so it can't crank, reach up the rear pump nozzle and feel the impeller blades. Sharp nicks and gouges mean it's been run in shallow or sandy water. Then check the clearance between the impeller tips and the wear ring around them — it should be tight, just a few thousandths of an inch. A worn, grooved wear ring lets water slip past, killing hole-shot and top speed.

Grab the impeller and try to wiggle the driveshaft. Noticeable play points to a worn pump bearing or driveshaft. None of this is catastrophic on its own, but it's leverage: a wear ring runs roughly $100–300 in parts and an impeller $200–400, plus labor, and a sluggish ski that 'just needs a wear ring' should be priced like it needs one.

• Dinged impeller blades plus a grooved wear ring equal soft acceleration — verify it on the water test, not just in the driveway.
• Wiggle the driveshaft for bearing play, and on Sea-Doos ask when the pump was last serviced and the driveshaft splines greased.
• Check the intake grate and ride plate for impact damage — bent or cracked means it hit something hard.

Go over the hull like an insurance adjuster

Walk the entire hull in good light, running your hand along it. You're hunting for stress cracks radiating out of the footwells, spider cracks along the seam where the top and bottom halves bond, and deep gouges on the keel from being run up onto rocky beaches. A little cosmetic scuffing is normal; structural cracks and evidence of a hidden repair are not.

Signs of a past hull repair — mismatched gelcoat color, sanding scratches, ripples, or a patch that's a slightly different texture — aren't automatically disqualifying, but you need to know why it was fixed and how well. Then open the seat and look inside the hull: standing water down there means it's taking on water somewhere, whether a bad drain plug, a failed carbon seal at the driveshaft, or a crack. Sniff for raw fuel and heavy mildew while you're in there.

• Cracks at the bond line or around the footwells can mean the hull was pounded hard or dropped — press on them and see if they flex.
• Water sitting inside the hull is a red flag; find the source before you buy, because a chronic leak sinks skis and rots foam.
• A repaired hull demands a discount and a straight answer — 'I don't know, I bought it that way' is your cue to look harder or leave.

Salt versus fresh — and proof it was flushed

Saltwater doesn't ruin a PWC; neglected saltwater does. Salt corrodes exhaust manifolds (cast Sea-Doo manifolds are notorious for it), aluminum housings, motor mounts, and every electrical connector it can reach. A saltwater ski that was flushed and rinsed after every single ride can be in great shape; one that was parked wet is a corrosion time bomb that looks fine until a manifold fails and dumps water into a cylinder.

Open it up and hunt for green or white crust on connectors, chalky aluminum, and rusty hardware. Best of all, ask the seller to flush it in front of you — connecting a hose to the flush port and running the engine before the water goes on, then shutting the water off before the engine goes off. Someone who does it smoothly and by the book has done it a hundred times. Someone who fumbles it or refuses probably hasn't.

• Inspect the exhaust manifold, connectors, and fasteners for corrosion — salt damage hides under covers and inside the hull, not on the shiny topside.
• A saltwater ski with a documented flush-every-ride habit can be a great buy; an undocumented one should be priced for the risk.
• Confirm the flush order is right — engine on before water on, water off before engine off — and that the telltale (pisser) stream runs steadily, because fumbling that order is how water gets pushed back into a cylinder.

Superchargers add power and a maintenance clock

If you're eyeing a high-performance ski — a supercharged Sea-Doo RXP/RXT/GTX (255, 260, or 300 hp), a Yamaha SVHO, or a Kawasaki 300 — understand that the supercharger is a scheduled-maintenance item, not fit-and-forget. Older supercharged Sea-Doos in particular used ceramic components in the clutch that Sea-Doo recommended rebuilding on an interval (historically around every 100 hours). When those parts fail on an older unit, debris can go straight into the engine — a repair that can cost more than the ski.

So for any supercharged model, ask for the supercharger service records specifically, separate from oil changes. If the seller can't tell you when it was last rebuilt on an older Sea-Doo, assume it's due and budget several hundred dollars for the service — or walk. On any forced-induction ski, don't let 300 horsepower distract you from a compression test; boost hides nothing and punishes a weak cylinder.

• Demand supercharger rebuild history on older supercharged Sea-Doos — a self-destructing ceramic washer can grenade the whole engine.
• No records means you inherit the maintenance clock; price in a rebuild or choose a naturally aspirated ski for lower-stress ownership.
• Higher horsepower means higher stakes on every earlier check — compression, corrosion, and pump wear all matter more, not less.

Inspect the trailer — you're buying two vehicles

The trailer gets ignored until it strands you on the shoulder with a smoking hub. Give it the same scrutiny as the ski. Trailer bearings are the classic killer: spin each wheel and feel for grinding or roughness, and look for grease slung on the back of the hub, which means a leaking seal and bearings about to fail. Check the frame for rust — especially on any trailer that's been backed into salt water — and the tires for dry rot and a date code more than five or six years old, regardless of tread.

• Spin the wheels and feel for bearing grinding; repacking or replacing bearings before a long tow beats a roadside failure.
• Check tire sidewalls for cracking and read the date code — marine trailer tires rot from age and sun long before the tread wears out.
• Confirm the winch strap isn't frayed, the coupler and safety chains are solid, and every light works before you leave the driveway.
• Make sure the trailer has its own title or registration where your state requires it — a ski you can't legally tow home is only half a purchase.

Verify the title, registration, and HIN

A PWC is a registered vessel, and clean paperwork is non-negotiable. Locate the 12-character Hull Identification Number stamped into the transom, typically on the upper starboard side, and confirm it matches the title and the registration exactly. Look closely for signs the HIN was re-stamped, ground down, or covered — that's a stolen-vessel red flag, not a quirk. Get a proper bill of sale, and confirm there are no unpaid registration fees or liens, because those follow the hull to you.

This is also where the seller's track record earns or loses your trust. A private seller who hands over service records, matching numbers, and a clean title is telling you something. If you're buying from a dealer, it's worth a few minutes to check their reviews first — weighting verified proof-of-purchase reviews and any written months after the sale about how warranty and service claims were actually handled — because a clean HIN means little if the shop behind it disappears when something breaks.

• Match the HIN on the transom to the title and registration character-for-character, and treat any tampering as a hard stop.
• Confirm there are no liens or unpaid fees before money changes hands — they transfer with the vessel, not the person who owed them.
• Confirm the seller's name matches the title and their photo ID before you hand over a dime — buying from anyone who isn't the registered owner is how you inherit a title dispute.