Glossary . . . Pump Items 

Nozzle, Wear Ring, Wear Ring Knock, Impeller, Intake Fairing, Jet Pump Case, Pinion Shaft

Real Name:         Nozzle

Common Name:  Nozzle, Snout, Cone, etc.

Function:            Two-fold: First off, it "straightens" the water that is being spun/thrust out by the impeller (enclosed propeller). Secondly, it narrows-down the diameter of the water stream - increasing the thrust being developed.

Pic:                    Here's a 3d version of a nozzle and here's a pic


  1. Early 50hp bikes had the shortest pump shaft, nozzle with smooth tip and raised inner flange.
  2. When changing to a Skat Trak impeller, you might have to machine-down that inner surface so that the impeller won't make contact.


Real Name:         Wear Ring

Common Name:  Wear RIng

Function:            Replace-able collar that surrounds/encapsulates the impeller.

Pic:                    Here's a 3d version of a wear ring and here's a pic


  1. Early 50hp wear rings probably didn't have the alignment knocks and o-rings in them
  2. Although some folks have tried to repair them with various techniques (bondo, ss liner, etc) it's usually most cost effective to just replace them
  3. If yours is grooved, then the holeshot will be greatly decreased.


Real Name:         Knock, Wear Ring

Common Name:  Alignment pins, knocks, sleeves, etc.

Function:            Two-fold: First off, it "seals" the joint between the wear ring and the pump. It also may help with alignment of the two pieces. The o-rings ensure a water-tight connection.

  1. There has been more than one manufacturer of the wear rings. So . . . sometimes the alignment/fit may need a little massaging to get to work right.
  2. Corrosion can wallow out the holes a bit making the knock fit very loosely and/or not at all.
  3. Sometimes they get stuck in the pump - sometimes in the wear ring

Real Name:         Impeller

Common Name:  Impeller, Prop, Screw

Function:            Generates thrust. Creates great frustration if worn or chewed up. Makes great paper weight.


  1. 50hp bikes had the what is referred to as the "straight blade" aluminum prop.
  2. Later years came with what is referred to as the "clipped-ear" impeller. Also referred to a the "high-altitude" impeller
  3. Aftermarket impellers were available in aluminum (maked HP), Bronze, and Stainless Steel
  4. Skat Trak is the only company offering impellers anymore (that I know of)
  5. They are all left-handed thread and can sometimes be a bear to get off. DO NOT take a grinder to it to remove it - you might do this

Real Name:         Intake Fairing

Common Name:  Speed Plug

Function:            Straightens out the water flow by reshaping the roof of the pump intake. Greatly increased the high-speed performance of a wetbike

  1. There has been more than one manufacturer of these things. Some are fiberglass, others were aluminum (welded in).

Real Name:         Case, Jet Pump

Common Name:  Pump

Function:            Houses the gears, shafts, and oil connecting the powerhead to the impeller. Serves as a the mechanism to mount the ski to the wetbike.

  1. Early 50hp pumps had 2 roundish zinc anodes mounted to the front pump cover
  2. 60hp pumps had the 2 oval anodes mounted to the back rear corners.

Real Name:         Pinion Shaft

Common Name:  Pump shaft, input shaft

Function:            Connects powerhead crankshaft to ring/pinion assembly (transmission).

  1. 50hp pumps had a short shaft
  2. 60hp pumps had the longer shaft
  3. You can put a 60hp motor on a 50hp pump but you cannot put a 50 on a 60 without changing the pinion shaft




Copyright 2012 Capt'n Obveeus


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