SoCal Jet Boats

Tech Talk => Jet Pumps => Topic started by: quick olds on October 02, 2011, 04:06:49 AM

Title: cavitation marks?
Post by: quick olds on October 02, 2011, 04:06:49 AM
Ok so I was lookin at my impeller and there are like corrosion lookin marks all over but never ran in salt my jetski buddies says skis get like that from cavitation is it possible in a boat I've never felt it cav and never had it out of the sTern besides on the trailer  :banghead:
Title: Re: cavitation marks?
Post by: quick olds on October 02, 2011, 04:21:20 AM
Water not stern Damn smart fone
Title: Re: cavitation marks?
Post by: BIG JOHNSON on October 02, 2011, 07:31:26 AM
Having my pump rebuilt right now. Cavitation burn is caused by a rough leading edge on impeller blades. You don't have to feel it driving the boat for it to happen. Air bubbles trail the rough edge and the bubbles turn into a gas and shit happens. Can't remember the exact process but mine was all pitted looking from that as well.
Title: Re: cavitation marks?
Post by: quick olds on October 02, 2011, 01:05:40 PM
Well deff won't take it to the place that rebuilt it before than they said it was fin and i only have a couple runs on it
Title: Re: cavitation marks?
Post by: wizard612 on October 03, 2011, 08:41:11 AM
Cavitation burn occurs when water flows over a surface and due to the speed/shape or surface condition, creates a low pressure area literally causing the water to boil.  It can be from a dinged up leading edge on an impeller but can also be from too much cup in the blades, too rough a surface, casting flaws, Too small an impeller cut etc.  Think of a small stream with rocks in it, as the water flows around the rock it creates an eddy behind it, that's the areas that if going fast enough would lower the pressure to the point that the water will boil. 
Title: Re: cavitation marks?
Post by: quick olds on October 03, 2011, 12:26:30 PM
I'm running an a cut impeller
Title: Re: cavitation marks?
Post by: 75 fantasy on October 03, 2011, 01:04:35 PM
wow, i didn't even tkink about that.  :-[ i learned something new today.
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