2005 challenger 180 SCIC SEVERE CAVITION won't go over 6krpm or 10mph.

[gtibananaboat]

Just spent 10k on a nice seadoo challenger , love the boat and the first time I took it out I could tell it have minor cavitation issue but I could get it on plane if I babied it. Next time out I put 4 people on it and it fell on its face . Can't go over 10mph or go over 6k rpm without slipping/cavitating like crazy . I can see some scoring on the wear ring but from what I can tell the impeller looks great.... one thing I did find was that the plastic collar that screws into the impeller came loose and is just sitting on the drive shFt . What are yalls thoughts ?

 

[gtibananaboat]

Here's a pic of what I'm talking about . That collar in the google pic on the left is just sitting on my shaft when it should be screwed into the impeller I believe .

 

[JPass]

That collar definitely needs to go back on. Impeller looks good, but you need to measure the gap between the wear ring and the impeller blade. I believe the max clearance is 0.35 mm or 0.14 in.

 

[gtibananaboat]

wouldn't you be able to tell if its been worn down? it looks like clean smooth plastic but with scoring and scratches in it in some places from debris.

 

[JPass]

wouldn't you be able to tell if its been worn down? it looks like clean smooth plastic but with scoring and scratches in it in some places from debris.

Usually if you shine a light through the steering nozzle and look from the intake grate side and see light around the impeller, then your clearance is too great. You really need to check the gap with a feeler gauge to be certain your clearance is within spec.

The collar being mid shaft is definitely creating some bubbles which could be some of your cavitation issue.

I guess you could try to put the collar back on and see if this alleviates your issue, if it does not, then break out the feeler gauges and check your clearance.

 

[pete63]

Usually if you shine a light through the steering nozzle and look from the intake grate side and see light around the impeller, then your clearance is too great. You really need to check the gap with a feeler gauge to be certain your clearance is within spec.

The collar being mid shaft is definitely creating some bubbles which could be some of your cavitation issue.

I guess you could try to put the collar back on and see if this alleviates your issue, if it does not, then break out the feeler gauges and check your clearance.

i see what you mean...
you need that back on and pull the pump check the bearing and grease condition. as jpass says it could be the cap causing cavitation. i zoomed in on the picture, to me i would change the wear ring. it may have some grooves worn in, impeller may have a flat spot.
feeler gauge wont pick up the grooves.
i would pull the pump, check re-grease pump bearing etc at same time check/replace wear ring .

 

[Coastiejoe]

The entire thing needs removed. With the collar (seal) not being on the impeller, water is now in the bearing area. Total tear down, clean up, check the bearings.