How To - Blueprint that Pump, Impeller, and Stator/Nozzle

Parts Needed, Tools Needed, Step-By-Step, Notes

Topic:                           Blueprinting pump assembly - hints provided by Wbbrian

Expertise Required:      Minimal

Estimated Time:            2 Hours

Parts Neeed:                 None - unless you are replacing the wear wring, impeller, nozzle bushing or shaft seal

Tools Needed:               You will need the following tools:

  • 14mm wrench or socket (with long extension)
  • Big MO crescent wrench (12 in or longer) - to hold pump shaft
  • Another Big MO crescent wrench to remove impeller
  • Large Flat File - and wire brush to clean it out with
  • Small die grinder with 3m type of pad
  • Metric tap for ski mounting bolts
  • Mapp Gas propane torch - for stubborn fasteners
  • Razor knife (box cutter)
  • 4 inch grinder with flap wheel (optional)

Step-By-Step:               Here's how to get it done

  • Remove the pump/ski from the bike - it will save you hours. Before you do, reach in and see if there's excessive play in the shaft (that would allow the impeller to contact the wear ring). It might be time to replace the nozzle bushing and seal.
  • Remove the ski and cleanup the mating surfaces and run a tap through the holes. If you pump looks like this, then it's been loose for way to long.
  • Remove the nozzle (take off the insert step-by-step procedures> 
  • Remove the impeller - stick one of the Big MO's through the pump intake and place firmly on the flats on the shaft (to hold it still). Place the other Big MO on the impeller and remove - TURNING CLOCKWISE (it's a lefthand thread)
  • Remove the wear ring - if you didn't remove the ski, then you'll need to remove some of the studs. Double-nut them and carefully back them out
  • Inspect all parts and decide if the impeller and wear ring are useable (this one is NOT ). New, tight-fitting parts will give best performance. Skat Trak 11/13 impeller will give best holeshot and midrange
  • Pump - take a few minutes to smooth out the inner surface. If you look close, then you'll see all kinds of casting flash - and - a very rough texture overall. If you polish it, cool. But you'll get the same result if you just paint it (smooth surface) - Black Epoxy works pretty good. And . . . you should install a speed plug.
  • Impeller - Clean up (sharpen) the leading edges. If you're up to it, polish that baby
  • Wear Ring - not a whole lot you can do here really. If there's a groove in it, replace it. If you are short of cash - add a couple of space washers onto the shaft to space the impeller back a bit. If your bike is pre-1985, be careful that the impeller won't bottom out against the nozzle. Make sure you have the knocks and o-rings. Replace them if they're all used up.
  • Nozzle - take the time to dress up the edges of the veins and remove any boogers that are on the inside surface of the stator. Here's an example. Also, see if you can smooth-out the inside of the cone after the stator. Every little bit helps. If your nozzle looks like this, it's time to get it welded up or just replaced. Now is the perfect time to replace the bushing and seal if needed. Remember that this seal goes in backwards (spring seal is FACING out)
  • Change the oil in the pump now. Then you can clean everything up and prepare for reassembly.
  • Clean all surfaces thoroughly - the wear ring mating surface - and - the ski mounting surface.
  • Install the impeller (remember that dab of anti-seize). No need to try to tighten it too much - it'll tighten up the minute it's run in the water
  • Install the wear ring and nozzle. I use a small dab of Black Silicone around the edge to prevent any pressure loss
  • Install the ski - look here for the particulars
  • After the 5200 cures, take the time to clean any excess off. Flip ski/pump over so that you are looking at the bottom of the ski. Take a razor knife and remove an excess 5200. Look close to see if the lip of the pump is sticking up above the surface of the ski. Take a 4 inch grinder and level things out. Then, take your rat-tail file and smooth out the front lip of the intake (to remove any sharp edges
  • Reinstall your modified scoop with 5200. Use a dab of it on the bolts - keeps them from falling out. Note - be sure you have run a tap through the holes all of the way to the bottom - and - use compressed air to blow holes clear.


Saltwater use dictates that all raw aluminum surface need protection. Not so necessary on the impeller but very necessary for the pump and nozzle inner surfaces. Here's some of Wbbrian's work

Impellers can be tough to get off. Don't use a powertool and try to cut them off - you'll ruin the shaft. Use a Torch and put some heat on it first.

Always use some anti-seize when installing the impeller.



Copyright 2012 Capt'n Obveeus

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