Freestyle Spinning Impeller or Cavitation

[IS0LD0UT]

How do you tell the difference between a impeller that is pitched too low and a leak causing cavitation.


I was running a 13/18 Hooker, Skat Mag combo with my 5mil. I was ok, I thought it was maybe overproped a bit. I ordered a hooker 11/17 and installed it, not my first time installing a prop by the way.
The engine revs fast in water and I cannot get up to speed and sounds a bit funny. I think its slipping but I have not felt what that is like before so I am not sure.

 

[Schmidty721]

I'm curious as well. I'm running a 10/16 in a stock pump and want to try a 9/15 but am afraid I may "spin" the prop.

 

[IS0LD0UT]

I think I am going to try to repitch it to 12/17 and see how it goes.

Wil changing to a shorter cone make it a difference when its slipping? Or is that just a really fine tune?

 

[Schmidty721]

I would think you would want a larger cone to occupy more volume in the pump to build pressure faster

 

[TheBuzzard]

if you think its slipping from an air leak, take off the intake grate and silicone the rubber seal from the inside. that will eliminate that spot as an air leak.

 

[IS0LD0UT]

Good idea. I was hoping someone would chime in, with. "yeah they feel about the same, your probably just under pitched."

 

[CRJ]

i felt a big difference with my 11/17 in my ski. my SN hops right out of the water, im running a 762 61x/61x on 93

 

[tomski]

Reinstall the original impeller and retest.

 

[IS0LD0UT]

I just pitched it up to a 12/17 going to try it out tomorrow.

 

[tomski]

Could have just bent the original one then.

 

[IS0LD0UT]

True. Wasn't sure how hard it was going to be to repitch. Pretty easy. 2 hookers is not a bad thing.

 

[IS0LD0UT]

Turns out it was a fouled plug. What a rookie I am. The 12/17 does seem like an improvement from the 13/18. Now I need to try the stubby mag cone.

 

[Harbor]

I have the 11/17 and stubby with 144 mag. 8 mil non pv, works great

 

[IS0LD0UT]

^ I may have to pitch it back down. Doh.

 

[kevbo]

If you have an air leak or protrusion like grate bolts, it will vibrate wihile underway at mid to high power. A large hub that is too flat tends to struggle when the ski is first dropped in and not moving forward..