Results 1 to 7 of 7
  1. #1

    '09 FX HO - Normal to "spin" when dumping throttle from stand still?

    Hi All -

    I've got an '09 FX HO that I like a lot - it's new to me as of a couple of months ago. I've noticed that, unlike my VX, if I go WOT from a stand still, it just pegs the rpms and does not accelerate hard. To get the best hole shot, I have to manage the throttle and ease into it.

    Is this normal? I know it's probably like a car (meaning dump the throttle, spin the tires) but wanted to ask. If normal, anything I can / should do to help the hole shot?

    Thanks!


  2. #2

    Join Date
    May 2007
    Location
    Minneapolis MN
    Posts
    838
    +1
    127
    It's hard to assess the level of acceleration without being on the boat but if you think it revs too much, it probably does. The first thing I would look for is an obstruction in the pump inlet tract and do a visual of the impeller. Look for erosion, nicks, a large gap between the O.D. and the pump liner, etc. Also, if the boat was modified by the previous owner for more speed the impeller may not be pitched correctly. Post some pictures if you can.

  3. #3
    Quote Originally Posted by pro1200 View Post
    Look for erosion, nicks, a large gap between the O.D. and the pump liner, etc.
    Hey, thanks for the reply!

    I checked it out before I bought it and, other than a little bit of surface rust (like 3m in one spot), it looked good. I didn't check for a gap between the impeller and liner but that would be easy enough - any idea that the tolerance should be? If bad, is it a matter of replacing the impeller or more involved?

  4. #4

    Join Date
    May 2007
    Location
    Minneapolis MN
    Posts
    838
    +1
    127
    If I remember correctly the allowable impeller/liner clearance is only about .010 inch. It's pretty hard to check without removing the pump so I would just do a visual. What is your peak engine RPM?

  5. #5
    Quote Originally Posted by pro1200 View Post
    If I remember correctly the allowable impeller/liner clearance is only about .010 inch. It's pretty hard to check without removing the pump so I would just do a visual. What is your peak engine RPM?
    Peak RPM seems to be about 7600.

    I might be describing what I'm experiencing incorrectly... Let's use the car again. Like a high horsepower car without traction control, if I nail the throttle on the ski from a dead stop it with tach up to 7600 quickly and will take off - just not nearly as fast as if I ease into the throttle - again, like a car. The ski seems to need to "hook up" to the water like a set of tires need to.

    Once I'm on a plane, I can nail the throttle and it accelerates like crazy - it's just from a dig that I notice it.

    Thanks again!

  6. #6
    How many hours does the ski have as it may be cavitation which can occur when the impeller is worn. You can either have the impeller "refreshed" or purchase a whole new one so long as the liner (housing directly around the impeller) is all good.
    A refresh is about 1/3 the cost of a new one.
    cheers
    NFI

  7. #7
    Ski Hacks MG's Avatar
    Join Date
    Apr 2013
    Location
    Georgia
    Posts
    5,253
    +1
    990
    You are experiencing cavitation. Check your prop and wear ring for nicks, chips and dings. Also consider a pump shoe kit.

    http://en.wikipedia.org/wiki/Cavitation

    Thanks,
    CCW

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Buying '09 FX HO tomorrow... What to look for?
    By nunyagd in forum Yamaha PWC Performance (4-stroke)
    Replies: 16
    Last Post: 07-24-2014, 08:05 PM
  2. 08-09 FX HO Fuel Economy
    By RonJon in forum Yamaha PWC Performance (4-stroke)
    Replies: 1
    Last Post: 02-05-2009, 08:20 PM
  3. 09 FX HO vs SHO
    By inothome in forum Yamaha PWC Performance (4-stroke)
    Replies: 8
    Last Post: 02-01-2009, 12:27 PM
  4. Who's Getting An '09 FX HO ???
    By amgad131 in forum Yamaha PWC Performance (4-stroke)
    Replies: 19
    Last Post: 10-17-2008, 10:51 AM
  5. Changing oil in FX HO?? how to?
    By r33pwrd in forum Yamaha PWC Performance (2-stroke)
    Replies: 5
    Last Post: 05-26-2007, 12:19 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
  •