Page 1 of 2 12 LastLast
Results 1 to 10 of 14
  1. #1
    Banned User
    Join Date
    Jun 2010
    Location
    Milwaukee WI
    Posts
    16,709
    +1
    1,324

    cavitation issues

    I pulled the prop on my pro 1200 over the weekend to try it out on my x45. When I got it out, I was shocked to see the same damage to the outer edges of the impeller I saw when I first got the boat. Originally the wear ring was damaged, so I replaced that and spent 140 bucks to have the prop refurbed. I pulled the prop after maybe 15 hours of run time and it looked awful. Definitely from cavitation. The ski shows no signs of it, the performance is flawless with no signs of slipping on take off at all. The stator is good, no damage to the vanes except for maybe a few very small nicks on them. I mean small, like the size of a pin head at worst. I don't really know where to look next. Ride plate was sealed recently. I have not checked the drive shaft seals, so maybe that's where I will look next.


  2. #2
    Rasta Mon Condoms We Be Jammin!!!!! TxPro1200's Avatar
    Join Date
    Aug 2006
    Posts
    5,445
    +1
    313
    wear ring you mean pump housing thats mounted to the hull correct.

  3. #3
    Banned User
    Join Date
    Jun 2010
    Location
    Milwaukee WI
    Posts
    16,709
    +1
    1,324
    Quote Originally Posted by TxPro1200 View Post
    wear ring you mean pump housing thats mounted to the hull correct.
    Yes

  4. #4
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    34,484
    +1
    933

    Arrow Driveshaft bearing carriers; Sources for replacement bushings

    What does the cavitation damage on that impeller look like?

    Photos?

    When the impeller was installed were there any sharp or rough edges on the blades?


    I am starting to think we have been generally too relaxed regarding bushing wear on the through-hull carriers. Going forward I am going to lean towards always replacing the bushings along with fresh seals.

    With fresh seals running on unworn driveshaft surface with good bushings the seals should prevent air ventilation of the jet pump from inside the hull. Worn bushings could allow the carrier to wobble and vibrate around the driveshaft and accelerate the wear of the seal lips, along with allowing air to get sucked past the seals.

    The OEM Polaris part number for the bushings is 3576514

    Randy at WeberPower sells OEM style Teflon impregnated sintered brass bushings as part of the rebuilt kit with new seals (103690).
    Also sells the complete new assembly 402423.

    John Zigler (Watcon) sells the 311501 aftermarket carrier with steel bearings.

    'Generic' 14DU06 sintered brass bushings are also available.

    Last edited by K447; 09-04-2012 at 09:38 AM.

  5. #5
    Rasta Mon Condoms We Be Jammin!!!!! TxPro1200's Avatar
    Join Date
    Aug 2006
    Posts
    5,445
    +1
    313
    got a very low hour seal carrier,pro style.bought it for the tx with triple pipes.got like 10 hours on it on a new driveshaft.

  6. #6
    Banned User
    Join Date
    Jun 2010
    Location
    Milwaukee WI
    Posts
    16,709
    +1
    1,324
    The original impeller was a brand new refurb that I had sent out to Skat Trak. There was the exact type of damage on it I am seeing now again. The only thing that was on the prop were a couple of small pits from imperfection in the welding of the outer edge of the blades. Otherwise the prop was in perfect condition. This is the prop before it was ever installed. I will try to get a pic of it when I remove it from the ski again. The prop looks like the edges of it have been completely sandblasted away.


    Click image for larger version. 

Name:	IMG_0536.jpg 
Views:	69 
Size:	86.5 KB 
ID:	282182Click image for larger version. 

Name:	IMG_0537.jpg 
Views:	63 
Size:	119.6 KB 
ID:	282183

  7. #7
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    34,484
    +1
    933
    A few ideas;

    Review the edges, surface transitions and sealing from jet pump tunnel into the 'shoe' and the pump base. Look for raised edges or lips where the water flow would catch and become non-laminar. Metal edges and even raised ridges or hollows of sealant can disturb the water flow.

    What you want is the water flow around the entire inside perimeter of the pump wear ring to flow water smoothly and without turbulence from the farther forward areas.

    Review where the pump base is positioned relative to the pump tunnel. Perhaps the base needs to be raised or lowered a fraction to better align with the hull tunnel.

    Upgrade to an 8 or 12 vane stator. Increased back pressure from the stator will increase water pressure around the impeller. Increased water pressure reduces cavitation.

    A smaller pump exit nozzle would also boost pump internal pressure.

    A more aggressive scoop intake grate would increase pressure at the impeller once hull speed picks up.

  8. #8
    Banned User
    Join Date
    Jun 2010
    Location
    Milwaukee WI
    Posts
    16,709
    +1
    1,324
    I have a 785 intake grate on it, which is stock. I like the 8 vane stator idea, but I have no idea where to find one. I looked in the pump tunnel and nothing seemed to strike me as odd. The only thing I can think of is that maybe the slightest imperfection in the impeller surface caused this to happen again. One of the blades shows almost no damage, the other two blades are worse.

  9. #9
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    34,484
    +1
    933
    Quote Originally Posted by BryanP View Post
    I have a 785 intake grate on it, which is stock.
    The JD intake grate is almost a shovel! Will slow you down but I expect it would jack up the tunnel pressure significantly.

    I like the 8 vane stator idea, but I have no idea where to find one...
    In my impeller collection at the gathering!

    Eight and twelve vane stators are out there, just keep your eyes open. Lugs may have a stack of them somewhere

    Do read up on how those stators may need a different spacer to avoid impeller blade interference.

  10. #10
    Rasta Mon Condoms We Be Jammin!!!!! TxPro1200's Avatar
    Join Date
    Aug 2006
    Posts
    5,445
    +1
    313
    my pro was bad about bbq nujet props during sharp turns from a takeoff,would just peg the rev limiter,the skats never did it.biggest reason i went to a long shaft setup,no more problems running the nu-jets

Page 1 of 2 12 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Cavitation Issue
    By Hockey369 in forum Yamaha Old School Skis
    Replies: 12
    Last Post: 06-25-2008, 09:36 PM
  2. Prop Spin/Cavitation Issues Resolved.
    By ba6636 in forum 4-Tec Performance
    Replies: 8
    Last Post: 06-20-2008, 06:40 PM
  3. 96 XP cavitation issues after sharp turns
    By r4ma1r in forum 2-Stroke Performance
    Replies: 5
    Last Post: 05-28-2008, 06:29 PM
  4. Cavitation issues..Ultra 150
    By BrandonB in forum Kawasaki Open Discussion
    Replies: 9
    Last Post: 06-09-2007, 05:37 PM
  5. Cavitation issue: worried
    By BDNJ in forum 4-Tec Performance
    Replies: 62
    Last Post: 09-13-2005, 08:21 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •