The full 12-month DFI service

The full 12-month DFI service

Watch the walkthrough

Watch on YouTube ↗ · Jetboard Australia — "Jetsurf DFI Yearly Service Tips, Save those frustrating breakdowns" (~52 min). Timestamps below follow the video's own time. Compare JETSURF USA's service schedule.

The same service covers every DFI model — Adventure, Race, Titanium, Cruiser. In salt water, do it every 12 months regardless of hours — a lightly-used board sitting unserved is often worse off than a heavily-used one. This walkthrough is the whole job, and it links out to the deep-dive guides for each sub-assembly.

Before you start — 2:20

• 2:25 — Run the board on the hose first to gauge its condition and chase any noise the owner has reported.
• 3:56 — Use Lanox, not CRC or petroleum-based sprays — petroleum sprays swell the rubber hoses and fittings, and swollen hoses let water in where it shouldn't be.

Remove the fuel tank — 3:03

1. 3:03 — Disconnect the fuel line and the fuel-pump power cable, lift the tank (hold it so the hoses don't tangle), pull the breather valve. Set the tank aside — it gets a proper check later.

Compression test — 3:50

2. 4:06 — Remove the red plug-cap lock, the cap, and the spark plug (JetSurf spanner). Pull the fuel injector aside so it can't get knocked.
3. 6:02 — Read the old plug — blacky-brown and lightly used here is healthy. Replace it regardless.
4. 6:23 — Fit a compression tester through the plug hole (Rod uses a home-made BSP adapter — a hose won't fit in there). Initialise the board and crank it.
5. 7:44 — Rod's gauge reads ~140 psi normal; anything over 140 is great. This one made ~150. Gauges vary — learn yours.

Starter clutch — strip — 8:14

6. 8:19 — Cover off (Allen key). How this area looks tells you whether the board's been lubricated every ride in salt water, as it must be.
7. 9:53 — Remove the engine cradle: 5 mm Allen key on a ratchet — the two primary mounts on the crankcases, one on the cylinder head (keep the washer), one underneath. This also frees the throttle cable.
8. 11:32 — At the throttle drum, turn the cable nipple and it drops out of its slot. Pull the cradle and cable clear. Account for every bolt.
9. 12:17 — Idler gear off first (key between the gears to lock, undo the bolt, wriggle it off its square drive). End cap off with a 32 mm socket (it's only on an O-ring).
10. 14:12 — Secure the crank (Allen key into the coupling hex socket) and undo the retaining nut. Slide the gear off — inspect the seal (worn or popped seals damage the main-bearing cage), and wipe the shaft (grooves = new crankshaft). Full detail: Starter clutch — check, service & the three types.

Lubricate the throttle cable — 16:35

11. 16:35 — Fit a motorcycle cable oiler — tape the JetSurf cable's lug-less end to seal it (a double clamp works best).
12. 17:59 — Flush it through with a graphite penetrant (Würth Rust Off) until lube comes clean out the handle end, then work it back and forth. Full detail: Freeing a sticky throttle cable.

Engine-bay checks — 20:30

• 20:36 — Check the two exhaust O-rings and the cylinder for black two-stroke-oil splatter — a sign of a leak.
• 21:01 — Check the coupling has a little gap and turns freely (they don't wear out).

Drive-shaft bearing — 21:20

13. 21:38 — The open stainless drive-shaft bearing lasts well if lubricated. Spray Lanox (or spray grease) into the bearing, or through the lubricator on newer boards, until it comes through and runs smooth. Do this every ride. Full detail: Jet pump & drive-shaft bearings.

Exhaust valve & silencer — 23:10

14. 23:16 — 5 mm Allen key, end screw out. There should be a copper ring here — a nylon washer won't pull it in (replace it).
15. 24:11 — Unscrew the end cap, pop out the ball and spring. Clean the (usually black) ball; check the seal in the plastic housing — a melted ball or bad seal lets water back into the engine.
16. 25:45 — Reassemble: stretch the spring slightly; fit the ball to the end it sits on, not sinks into; the eccentric goes cavity-outward and stays loose until the silencer is lined up to the ride plate, then tighten. Full detail: Exhaust systems explained.

Jet-pump bearings — 28:24

17. 28:31 — Undo the plastic end cap (5 mm) in the jet-pump housing. Green grease and no water = leave it. Water or moisture pouring out = pull the jet pump for new bearings and seals. Re-seat the O-ring with grease and refit.

Ride plate & impeller — 29:58

18. 29:58 — Check every ride-plate and fin-bracket bolt for tightness (they do come loose).
19. 30:46 — Run a finger over the carbon-fibre impeller's leading edges for chips or peeled laminate. Damaged = replace the complete impeller-and-shaft assembly (genuine JetSurf).

Starter clutch — reassemble — 31:54

20. 32:07 — Grease with the correct Klüber LDS 18 (what JetSurf uses) — around the seal, the end bearing, and the big rear seal. Don't over-grease — no room for expansion means heat.
21. 33:52 — Refit the gear, test (spins free one way, locks and drives the crank the other). Blue Loctite 243 on the retaining nut, tighten with the crank held. End cap on (not too tight).
22. 36:22 — Idler gear back on — Loctite on the gear (helps hold the press fit) and on its bolt.

Refit the throttle cable & cradle — 37:30

23. 37:35 — Refit the cable to the drum (full throttle, barrel through the slot, close the throttle, cable seated in the groove).
24. 38:21 — Route the cable under the little tab and on top of the crankcases (lift the engine to help). Photograph it before it disappears.
25. 38:57 — The engine-cradle spindles: the big-flange spindle holds the throttle cable against the crankcase boss; the long tabbed bolt holds the fuel-pump hose (tag into the cradle). Start both loose, then tighten.
26. 41:06 — Tighten the cradle bolts, then the two end engine mounts (lift the engine to line them up). Fuel hose back on, cover on.

Board & fittings — 42:40

• 42:48 — Check bindings (tear around the bolts), the side plastic fittings (break if stepped on), straps, the tether cable (frayed = replace), the throttle, and the snorkel's flexible joint.
• 43:45 — Look over the hull for grooves — a poorly-fitted fuel tank can rub right through the bottom of the board. Minor carbon/gelcoat nicks take epoxy.

Fuel tank — 44:36

27. 44:42 — Drain the fuel. Check the "teabag" fuel-pump filter isn't crusty and mop any debris from the tank base (the pump and filter aren't sold separately — a bad one means a new tank).
28. 46:25 — Test the one-way breather valve with a pop-off tester: blow into it and air should pass slowly into the tank. A blocked valve makes the tank suck in and the engine cut out; kink the tube and pump — if it holds pressure, it's blocked.

Refit the tank — 47:14

29. 47:56 — Breather tube on behind the rear strap (not in front — it kinks). Seat the tank on its rubber knob, do the strap.
30. 48:36 — Electrical wire on first (it's underneath), then the fuel-injection hose.

Spark plug & final checks — 48:43

31. 48:58 — Fit the right plug: NGK BPR7HS (the DFI plug is longer than the short carbureted-board plug). JetSurf tool, about a quarter turn past seated — no more.
32. 49:52 — Fit the plug cap the right way — the retainer piece sits around the hex on the plug to hold the cap on (a lot of people fit it backwards).
33. 50:19 — Run it on the hose: engine runs clean, mounts secure, no leaks, water through the exhaust and the telltale. See Is your board cooling properly?