Jetsurf Glossary

2T / two-stroke oil: The oil that keeps a gas board's engine alive. It travels in the fuel, not in a separate reservoir, which is why fuel is mixed at 50:1. Use fully synthetic. How to mix fuel →
50:1: The gas-to-oil ratio every gas JetSurf runs: 50 parts gasoline to 1 part two-stroke oil — 2.6 oz per gallon, 100 ml per 5 litres. How to mix fuel →
DFI: Direct Fuel Injection. The current gas engine, which injects fuel electronically. DFI boards use the 4-pin charger; older carbureted boards use 2-pin. DFI charger on older boards →
Carburettor (carb): The fuel system on boards before DFI — it mixes fuel and air mechanically. Needs periodic cleaning and tuning. Carburettor service →
Spark plug: The part that ignites the fuel. The fastest health check on a gas board, and a consumable — swap it every 6–10 hours. Spark plug check & replacement →
Compression: How well the engine seals when the piston squeezes. A compression test is the single best measure of engine health, and the first thing to ask for on a used board.
Flooded: Water where the fuel and air belong, usually after a fall. Don't keep cranking it — drain it first. Flooded board while riding →
Exhaust ball: A ball inside the exhaust that blocks water from reaching the engine. Clean it once or twice a year. Exhaust systems explained →

Jet pump / impeller: There's no propeller. The jet pump sucks water in underneath and fires it out the back; the impeller is the screw inside that does it. Suck up weed or sand and the board loses power. Jet pump & bearings →
Telltale: The small jet of water that sprays out while you ride, proving the engine is being cooled. No spray means head to shore. Is your board cooling properly? →
Cooling system: Water is drawn from the jet pump, run through the engine and exhaust to cool them, and pushed back out. Salt left in it is the main cause of corrosion. Blocked cooling system →
Flush attachment: The fitting that connects a garden hose to the board so fresh water runs through the cooling system after a ride. Non-negotiable after salt water. The flush attachment →
Freewheel: A one-way clutch between the starter and the engine: it drives one way and spins free the other. Part of the 6-point pre-ride check. Freewheel removal & installation →
Starter clutch: The clutch the starter motor drives through. Wears out, and comes in three different types depending on the board. Starter clutch →
Bilge pump: A small pump inside the board that clears water out of the engine space. It only runs when the board is switched on. Bilge pump removal & installation →
Snorkel: The air intake tube. Rinse fresh water down it after every ride — a lot of spray goes in there. Cleaning your board →

iCU / ICU: The Ignition Control Unit — the board's brain and battery pack in one. It comes out for service and for flying. iCU removal & installation →
Mapping the ICU: Reflashing the ICU with a fuel map suited to your altitude and conditions, so the engine runs right where you actually ride. Mapping your ICU →
Magnet key / shut-off key: The magnetic key that wakes the board and starts it, and cuts the engine the moment it comes away. Carry a spare — they're easy to lose. Starting your board →
Hand control / throttle: The handle you hold, with the throttle and the kill switch. Keep it inside the straps when you're not riding so it doesn't fill with sand. Hand control replacement →
Timing sensor: Sets when the spark fires. Out of position and the engine runs badly or not at all. Setting the timing sensor →

Booster: Push past the end of the throttle on an electric board for 1–2 extra horsepower for 10–30 seconds. It cuts out on its own to protect the battery. Electric board orientation →
Power modes: Three power levels on an electric board — low, medium, high. Count the buzzes to know which one you're in. New riders start in low. Getting an electric board ready →
Safe-return mode: When the battery light turns solid red, the board cuts power back and you have roughly 400 m / 1,300 ft to reach shore. Head in when the light turns red. Electric board orientation →
Storage mode: A charger setting that charges the battery to about 50% — the level a lithium battery is happiest sitting at between seasons. Charging an electric board →
Decompression chamber: A chamber on an electric board that you open and check for water before each session. Electric board — first ride →

Hull: The body of the board — carbon fibre, light and stiff, and the expensive part to damage. How to choose your board →
Bindings: The foot straps. Dual bindings are set up for regular and goofy stance at once; race bindings are single-stance and stiffer. Bindings explained →
Regular / goofy: Which foot leads: regular is left foot forward, goofy is right. Pads and bindings can be swapped to suit. Swapping the pads →
Ski: A JetSurf ridden standing upright holding a handlebar, like a stand-up jet ski. The handlebar comes off to ride it as a board. The board lineup →
SL / Super Light: The lighter build of a race board — less weight, more speed. The board lineup →
Pop-up: Getting from lying or kneeling to standing. The part everyone practises first. Your first pop-up →
Leash: The cord that keeps the board with you after a fall — worn on your arm, never clipped to the hand control or a single binding bolt. Leg ropes →

HIN: Hull Identification Number — the board's VIN. Marked on the hull and on the Certificate of Origin; they must match. Titling & registering →
MSO / MCO / Certificate of Origin: The board's birth certificate, issued once by the manufacturer. Your state keeps it when it issues your title, so don't lose it. Titling & registering →
Vessel registration: A motorized surfboard is a vessel in law. In Florida you have 30 days from purchase to title and register it. Titling & registering →

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