Jet Pump

Propulsion

Check impeller blades for damage or excess wear at blade edges.

Check stator vanes for damage

Jet pump ventilation can cause reduced thrust when accelerating from low speeds, yet at higher speeds thrust is just fine. Ventilation occurs when air gets drawn/sucked into the impeller.

Jet pump cavitation can have similar symptoms to ventilation, but the cause is usually damaged/worn/bent impeller blades or damaged/bent stator vanes.

If the impeller is not the original part number, check that the replacement impeller has the correct blade pitch for your engine power and hull.

Polaris PWC through-hull drive shaft seals

Water is leaking into the hull around the drive shaft

Check that the water is not coming from the small hose nipple on the speedometer pitot, which is directly below the drive shaft.

Best way to check for leaks is to strap the hull to the trailer front and back, back it down the launch ramp until the jet pump intake is submerged, and run the engine with the hull strapped down.

You can leave the seat off, and find out where the water is coming from.

Note: If the through-hull shaft seals are original, just replace them. The rubber has probably dried out, especially if your machine is from the 1990s.

Replacing the seals and bushing in the through-hull assembly

There are different versions of the through-hull bearingEarly units with crimped ends can not be repaired, but they can be directly replaced with the newer style assembly (1996-2004, except MSX)Click here for a list of parts sources The seals tend to wear more than the self-lubricating bearing/bushing, so you may not need to change the bearing, unless it is worn. Replacement seals can be purchased from any Polaris OEM parts source, or generic seals may be installed.

Polaris part number 3610040 has a stainless steel shell with rubber coating on the concave face, measures 38mm x 20mm x 8mm. I think the garter spring is also stainless steel.

Engine mounts must not be loose

Always check the engine mounting for looseness. Grab the top of the engine or exhaust and firmly push/pull the engine from side to side. There should be almost no engine movement as the rubber engine mounts will flex only slightly. If there is much movement at all, check for broken or loose engine mounts. Also check that the bolts underneath the engine that hold the engine case to the bed plate are tight. It is important that the engine not be able to shift around during operation.

After re-installation in the hull and the drive shaft is back in place be sure to pump grease into the through-hull bearing. You will need enough grease to displace the air pockets inside. Use a high-quality Lithium based waterproof bearing grease. Re-grease after every ride for the first few rides, until you are sure it is full of grease and all the air is gone.

Replacement bushings are Polaris part number 3576514 (2 required)

Apparently the generic equivalent plain bearing is 14DU06, a self-lubricating steel+sintered metal+impregnated Teflon bearing

WSM rebuild kit 003-117-01 is apparently no longer available.

WSM does offer a replacement through-hull product for non-MSX hulls. WSM 01-115-01 uses a steel bearings instead of bushings and must be greased regularly.

Generic Drive Shaft Seal carrier seal part# 8702 (Two required)