A board with roaring drive-shaft bearings — killed by no lubrication and a year in storage full of salt. This is the whole job: pump out, both sets of bearings and seals replaced, the impeller dressed back to shape, resealed, and the engine realigned.
Tools & supplies
Allen keys; 1/2" drive extension; long Allen-key socket on 1/4" drive; vice grips; 10 mm spanner
Jet-pump puller — a slotted steel bar + threaded rod (Booker rod) with washer and nut
Sockets sized to drive the new seals; belt sander (impeller); lathe or fine file (shaft)
New drive-shaft bearing (stainless) + seal; two jet-pump seals (JetSurf or stainless-spring)
Clear RTV silicone; ATF (bearing-housing oil); grease; Lanox / Inox spray; blue thread-lock; epoxy resin (impeller delamination)
Diagnosis — 0:14
1:12 — With the engine out, turn the drive shaft — this one is rough and noisy, the bearing rusty. Cause: it was never sprayed with lubricant, then stored a year full of salt.
4:27 — White residue in the jet-pump oil = water in the oil → the jet-pump seals need doing too.
Remove the coupling & collars — 0:52
1:37 — Undo the coupling Allen screws (one or two depending on model, often tight). It slides off — if not, jam a screwdriver in the coupling slot to spread it.
2:03 — Behind it: a locking collar — undo and remove.
2:11 — Down the back: a locking collar on the bearing itself — undo. That's the engine-bay end done. The bearing behind it is visibly rusted.
Remove the ride plate & tubes — 2:38
2:55 — Flip the board. Undo all the ride-plate screws and lift it off (this model has the silencer bracket built in). Fix any seized fin screws / missing bolts while it's off.
3:32 — Release the tubes — quick-release couplings, push the ring in. If tight, push the ring toward the jet-pump cavity with a screwdriver the same diameter as the hose and it pops out.
4:23 — Remove the two jet-unit retaining screws (Allen keys).
Break the silicone & pull the jet pump — 4:50
5:23 — Remove the plastic end cone (can be brutally tight). Persuade it with an aluminium drift and hammer against the end — the shock loosens the thread, then it unscrews.
7:07 — Break the silicone seal: the two solid points are the two pump fittings — pry gently under those only and you'll hear it crack. Never pry under the thin pump housing — it cracks.
7:55 — Undo the small grub/retaining screw on the bearing cap — long Allen socket on the cap, vice grips on the shaft underneath so it can't turn (shaft not turning = the screw is releasing).
8:53 — Fit the puller — the slotted bar across the end of the board, threaded rod into the hole the grub screw came from, 10 mm spanner. Wind it out; keep the shaft from turning. The silicone lets go and the pump draws out — finish with a gentle rubber-mallet tap.
Remove the drive-shaft bearing — 12:07
12:07 — Slip a 1/2" drive extension through the hole and soft-hammer the bearing out — it drops inside to the aluminium bearing housing (held by O-rings). Take the housing out.
12:50 — On the bench, pin-punch the bearing and seal out of the housing. This is a lubrication failure — the housing has a lube point fed from the board's lubricator; older boards have none, so their open bearing must be sprayed regularly (Rod: every ride).
Split the impeller from the housing — 14:01
14:08 — Use the same puller tool in the shaft thread (a pin punch works but marks the shaft). Rubber hammer only — steel hammer blows damage reusable bearings.
14:41 — As the impeller reaches the housing edge, tap it sideways so a blade can clear, then it pops out. The impeller is glued to the shaft — a new impeller comes as a shaft-and-impeller assembly.
15:26 — Inspect the pump housing — a chip in a vane here (something went through), not fatal. Dig its seals out for replacement.
Repair the impeller — 16:16
16:16 — The leading edges are chewed on all three blades. These are overlapping impellers (leading edge covers the trailing edge), and they're large for the power — you can take up to ¼" / 6 mm off the leading edge with little performance loss.
17:20 — Belt-sander: flatten the edge, remove the chunks, then reproduce the original curve (copy the least-damaged blade).
18:21 — Carbon-fibre delaminating at the back of a blade — epoxy-resin the gap, or remove the small peeling piece and dress the edge to a clean line (still strong, one lamination out).
19:35 — Sharpen each leading edge to a chisel point (flat one side, a touch on the back). A dull edge causes cavitation.
22:44 — Polish the shaft on a lathe (or fine file) — clean the corrosion and give the seal-running surfaces a fresh face.
Jet-pump seals & bearings — 23:26
23:32 — Hook the two leaking pump seals out. Check the pump bearings — smooth and good here, so leave them (they're expensive sealed units).
24:44 — Marine seal rule: fit each seal with the big lip and spring facing the water side (keeping water out matters more than keeping oil in). Use JetSurf or stainless-spring seals — plain springs rust in salt, fall off, and the seal leaks.
25:52 — Drive the seals in with a correctly-sized socket, a little spray on each. On the pump housing seal, big lip toward the jet-pump cavity.
28:17 — Fit an open bearing (so it can be lubricated) — flick the shields out of a sealed one if that's all you have.
Reassemble the jet pump — 28:36
29:02 — Pack grease between the seal lips — nothing else lubricates them, especially the outer one.
29:37 — Fit the impeller into the housing through the seals, seat it, rubber-mallet it home flush.
29:57 — Refit the end screw with thread-lock. Fit the coupling to the shaft and nip it so the shaft can't turn while you tighten the end screw (vice grips gently on the coupling to be sure), then take the coupling back off.
32:03 — Fill the bearing housing with ATF up to the thread, let it run to the second bearing, fit the end cap.
Reseal & install the jet pump — 33:02
33:14 — Clean all the old silicone off the mating face. Run two beads of clear RTV silicone around it.
33:47 — This seal is critical. Any air drawn in behind the pump seal aerates the water and the board cavitates and won't drive — a common "won't drive" fault after a DIY impeller repair. Leave JetSurf's alignment pad in place (it sets the pump to the ramp shoe).
35:03 — Slide the pump in (easier than it came out), fitting the hoses as you go. Push it fully home, wipe the excess silicone.
36:05 — Check the hose clips are out — clips out is what locks the hoses on. Tug to confirm. Refit the ride plate, tight.
Install the drive-shaft bearing — 37:00
37:07 — Flip the board back. Clean the housing cavity. Pack the seal with plenty of grease — it runs dry and scores the shaft otherwise. Grease the housing O-rings (check condition).
38:08 — Press the housing in, tap it home. Run the bearing down the shaft and tap it home with a piece of tubing.
38:50 — Fit the collar the right way — small end against the bearing (wrong way blocks the lube path). Push it hard against the bearing (bearing rotates with the shaft = it's home) and lock it — it stops the shaft floating, bearing not over-tight. Then the little locking collar.
40:08 — Leave the main coupling loose on the shaft — set it once the engine is in.
Engine & coupling alignment — 40:38
40:56 — Coupling position matters — wrong and you load the crank bearing and misalign the timing pickup, so the engine misfires.
41:04 — Rod removes engines by the fixed Allen-key bolts (not the slotted hex bolts), which keeps the factory drive-shaft-to-engine alignment — so no realignment is needed here. If you removed the hex bolts, you must align the coupling to the engine before torquing them.
42:20 — Check the cush drives are in place, spray the coupling, and slide it on — if it lines up straight, alignment is good. Rubber-mallet it home.
43:00 — Set it so the crank's end float is away from the coupling — the coupling must not push the crank sideways onto its bearing. Tap it back a touch more for extra clearance (the board flexes in use). Then tighten the coupling firmly and its retainer collar.
Tip: the drive-shaft bearing is stainless and takes a lot of salt — but it's an open bearing with almost no reservoir, so spray it with Lanox every ride and keep the seals packed with grease at every service. That one habit is the difference between this job and a five-minute lube.
Caution: only pry the silicone under the two solid pump fittings — the thin pump housing cracks. Re-seal the jet pump with RTV every time or it cavitates and won't drive. Marine seals go big-lip-and-spring toward the water. Set the coupling with the crank's end float away from it, never pushing the crank bearing.
Keep riding
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