How To - Choosing an Impeller

Choosing an ImpellerImpeller Choices, Stock 50hp, Stock 60hp, Added Scoop & Speed Plug, Heavily Modified

Topic:                           How do you choose the right impeller?

Expertise Required:      Jedi Master

Choosing An Impeller:   Which one is best for you? Good question . . . let's consider the following questions:

      • Do you have a 50hp bike or a 60hp bike?
      • How much do you weigh?
      • Do you have a scoop?
      • Do you have a speed plug?
      • Do you have any other mods (exhaust spacer, engine mods, etc)
      • Do you have a new wear ring?
      • Is your nozzle bushing in good shape?

With the above considered, then here's what I recommend (and note that others have their opinions that differ from mine)

Impeller Choices:           Here are the impellers that I know of - there might be more

      • Aluminum - stock STRAIGHT BLADE
      • Aluminum - stock CLIPPED EAR
      • Aluminum - used on Seaflash/Jetstars (never seen one but heard of them)
      • Stainless - SKAT TRAK 11/13 (used for stock bikes)
      • Stainless - SKAT TRAK 12/15 (big motor, lots of power required)
      • Stainless - 4 blade used on Seaflash/Jetstars
      • Stainless - 5 blade used on Seaflash/Jetstart
      • Bronze - Straight 13 degree

Stock 50hp:                  If you have a stock 50hp, then either the stock straight-blade aluminum or the clipped-ear impeller is a good choice. Here's a few things to make sure you're performance stays acceptable.

      • Wear ring - make sure it's a good one with no grooving or nicks
      • Impeller nicks should be ground down and smoothed out
      • Sharpen the leading edges of the impeller blades a little. Don't go crazy
      • Make sure the nozzle bushing is in good shape.
      • Adding a super-scoop is a good addition as long as you DON'T put in a speed plug too.
      • Adding a speed plug works good too - but modify the scoop like this

Stock 60hp:                   The aluminum clipped-ear impeller seems to be the best overall choice for this bike. The Skat-Trak stainless 11/13 is also a good replacement.


      • The skat trak will lose a mph or two on the top end, but has much better holeshot and midrange over stock. Many wetbikers agree that it's a good tradeoff.
      • Scoops - the Super Scoop works BEST without a speed plug, or works GOOD with a speed plug if modified, and the Ultra Scoop works best with a speed plug. The Pro Scoop works best with a speed plug.

Added Scoop - AND - Speed Plug:

               Which scoop is which? . . . look here

               If you have a speed plug (aluminum or fiberglass) then your choices should boil down to the following:

      • Aluminum clipped-ear - really good top end, good overall performance
      • Stainless Skat Trak 11/13 - excellent holeshot, and midrange
      • Bronze 13 degree straight pitch - little slower holeshot, but best top end

Heavily Modified

      • The trend here seems to favor the BRONZE 13 degree prop. Watercross of Texas even used to re-pitch these but I don't know what they final pitch was.
      • Since those bronze ones are hard to find, the Skat Trak 12/15 is another good choice.


      1. Running either of the above requires the nozzle bushing and shaft to be in good condition. Any wear/play there will quickly destroy the wear ring.
      2. Both of the above will probably require adding shims so that the leading edges of the impellers don't contact the pump casting.



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