Pumping mud
+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 14 of 21

Thread:
Pumping mud

  1. #1
    Junior Member
    Join Date
    Apr 2009
    Posts
    13

    Default Pumping mud

    Two weeks ago i ran a shitload of sand and mud through my berk 12jc-pump when trying to reach the beach. Before that the boat reached [email protected], today it only made 67mph, still at 5100rpm.
    I checked the impeller and it is not damaged, (atleast it is not worse than before). Where did my top-speed go? Any pointers?

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    mo balls than $cents$ IMPATIENT 1's Avatar
    Join Date
    Dec 2007
    Location
    hugo,okla
    Posts
    11,733

    Default

    you prob trashed the wearring

    Dare to be different, if it turns out great you can claim you planned it that way.

    Jetboatperformance.com

  4. #3
    No Longer Recovering 454Rocket's Avatar
    Join Date
    Dec 2007
    Location
    Torrance, CA - Havasu, AZ
    Posts
    916

    Default

    5 MPH can come and go with weight, air temp, a lot of things...

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    Senior Member LuckyDaze's Avatar
    Join Date
    Apr 2008
    Location
    Tacoma Wa
    Posts
    1,409

    Default

    Quote Originally Posted by 454Rocket View Post
    5 MPH can come and go with weight, air temp, a lot of things...

    And it can also come from an extra clearanced wear ring... I would check to see how loose your pump is now.

    ~Brian

  7. #5
    E-7 Sheepdog (ret) SmokinLowriderSS's Avatar
    Join Date
    Dec 2007
    Location
    Newton Ks.
    Posts
    6,834

    Default

    Quote Originally Posted by LuckyDaze View Post
    And it can also come from an extra clearanced wear ring... I would check to see how loose your pump is now.

    ~Brian
    Yep, shitload of crap pumped = shitload of more clearance ground into it, and shitload more high pressure water bypassing back into the intake.
    "As democracy is perfected, the office of president represents, more and more closely, the inner soul of the people. On some great and glorious day the plain folks of the land will reach their heart's desire at last and the White House will be adorned by a downright moron."
    H.L. Mencken

    OBAMA: Some people deserve this.
    The rest of us are being dragged along kicking and screaming.

  8. #6
    Boat Nut sleekcrafter's Avatar
    Join Date
    Dec 2007
    Location
    South Elgin, Il.
    Posts
    5,131

    Default

    To repair it takes a shit load of time, and a shit load of money, to fix
    Upper Midwest Power Boat Association
    DRAG BOAT RACING UMPBA #926


  9. #7
    mo balls than $cents$ IMPATIENT 1's Avatar
    Join Date
    Dec 2007
    Location
    hugo,okla
    Posts
    11,733

    Default

    Quote Originally Posted by sleekcrafter View Post
    To repair it takes a shit load of time, and a shit load of money, to fix
    lol not sooo bad if ya know how to repair yoself

    Dare to be different, if it turns out great you can claim you planned it that way.

    Jetboatperformance.com

  10. #8
    Senior Member coonass's Avatar
    Join Date
    Jan 2009
    Location
    Canyon Lake, TX
    Posts
    738

    Default

    Quote Originally Posted by IMPATIENT 1 View Post
    lol not sooo bad if ya know how to repair yoself
    Yes did the same to me last year ..............pull'n out a buddy that was stuck on a sand bar ................needless to say had to rebuild pump

    wear ring was shot

    and remember this next time .......................... whatever you are pump'n out of your jet drive is going into the motor so kill it and walk her to a deeper spot

  11. #9
    Member eugene-rus's Avatar
    Join Date
    Feb 2009
    Location
    Moscow, Russia
    Posts
    76

    Default

    Quote Originally Posted by LuckyDaze View Post
    I would check to see how loose your pump is now.
    How would one check the "loosness"? Disconnect the motor and try to move the shaft forwards and backwards?

  12. #10
    Crazy Eights Brad @ SCJB's Avatar
    Join Date
    Dec 2007
    Location
    Las Vegas, NV
    Posts
    1,476

    Default

    i thought pumping mud and blowing out wear rings only happened in san francisco


  13. #11
    Senior Member
    Join Date
    Feb 2008
    Posts
    546

    Default

    Quote Originally Posted by eugene-rus View Post
    How would one check the "loosness"? Disconnect the motor and try to move the shaft forwards and backwards?
    remove the bowl and then the impellor and take a measurement of the difference of the two. stock meas. on the od of the impellor skirt is7.225 and id of the wear ring 7.250 leaving an ideal .025 clearance. factory tolerance .025-.035. if you have for and aft movement you have a much greater problem.

  14. #12
    Sit N' Spin Jetaholic's Avatar
    Join Date
    Dec 2007
    Location
    Droppin' the kids off at the pool
    Posts
    1,423

    Default

    The fact that you're still able to hit the same max RPM value tells me that the pump is fine (loads the engine exactly the same as it did before). If the pump has loosened up, the RPM would more than likely increase (a loose pump won't load the motor as hard, thereby allowing the WOT RPM to increase, but top speed will either remain the same or drop due to a looser pump having less efficiency).

    Just my $0.02.



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

  15. #13
    Senior Member Xerophobic's Avatar
    Join Date
    Dec 2007
    Location
    Calgary, Alberta, Canada
    Posts
    418

    Default

    Quote Originally Posted by Jetaholic View Post
    The fact that you're still able to hit the same max RPM value tells me that the pump is fine (loads the engine exactly the same as it did before). If the pump has loosened up, the RPM would more than likely increase (a loose pump won't load the motor as hard, thereby allowing the WOT RPM to increase, but top speed will either remain the same or drop due to a looser pump having less efficiency).

    Just my $0.02.
    Yea thats what I was gonna say too.

    I also still dont buy that a single time pumping some mud/silt will trash a pump like that either. We do far far far FAR worse to our pumps all the time and they just dont show that kind of deficiency of performace. We start our boats in shallow water all the time, even race boats, because we have no choice and they just simply do not wear that way. Sure maybe after a whole season of doing it, but not one time.

    Something else isnt adding up

    Cheers
    If you ain't hittin bottom...you ain't jetboatin!

  16. #14
    Sit N' Spin Jetaholic's Avatar
    Join Date
    Dec 2007
    Location
    Droppin' the kids off at the pool
    Posts
    1,423

    Default

    Quote Originally Posted by Xerophobic View Post
    Yea thats what I was gonna say too.

    I also still dont buy that a single time pumping some mud/silt will trash a pump like that either. We do far far far FAR worse to our pumps all the time and they just dont show that kind of deficiency of performace. We start our boats in shallow water all the time, even race boats, because we have no choice and they just simply do not wear that way. Sure maybe after a whole season of doing it, but not one time.

    Something else isnt adding up

    Cheers
    Exactly, something else is going on. Did he add a passenger (passengers are worth about 3-5mph)? Did he have more beer or ice in the ice chest? Weight will affect top speed while top RPM remains the same (RPM is only affected by pump load, impeller cut, clearances within the pump, etc etc...not by boat's dynamic properties, i.e. weight, speed, etc).

    Was the diverter set to the same position as last time?

    Too many dynamic variables to mention.
    Last edited by Jetaholic; 06-18-2009 at 02:25 PM.



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

+ Reply to Thread
Page 1 of 2 1 2 LastLast

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in


Tags for this Thread

Digg This Thread

Posting Permissions

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

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95