Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 23
  1. #1
    SuperChief's Avatar
    Join Date
    Aug 2011
    Location
    Manchester, UK
    Posts
    12

    Question New prop = excessive reduction in RPM (and performance)??

    Thanks to troy, for pointing me in the right direction... Anyway here goes...

    I have an '08 RXT-X running a stock engine, when I first got the ski I saw RPMs as high as 8200, and performance was very impressive. After sucking a rock up and replacing the wear ring, and prop with a Solas item (either a 15-20R or a 15-22R I think) revs have dropped to an unreasonable 7200-7400 at WOT. I was told the prop would reduce revs but I think thats a little excessive, the performance and throttle response just seems to have gone!! All this running on 99 octane fuel in the UK... I'm not that experienced on these things, however that really doesn't sound like a healthy ski to me.
    Any help or suggestions, on what to look for perhaps, would be greatly appreciated

    Many thanks

    Tim


  2. #2
    MSRXP's Avatar
    Join Date
    Sep 2010
    Location
    Central MS
    Posts
    5,448
    +1
    7
    The prop isn't your issue. Not nearly 1k worth of loss IMO!

  3. #3
    Mod less, ride more! troyheb's Avatar
    Join Date
    Jul 2007
    Location
    Nederland, Texas
    Posts
    8,725
    +1
    1,267
    Ok. Rpm's @ 8200 is hitting rev limiter. Once we get you squared away on getting the rpms back up you want to be around 8100. 15/22 is to much for a stock ski with no mods, but I dont think you should have dropped to 7200-7400.
    If the prop is a 15/20 then it could be a boost leak. have you had any of the SC ot IC hoses off?
    Try and find out for sure what prop you have.

  4. #4
    SuperChief's Avatar
    Join Date
    Aug 2011
    Location
    Manchester, UK
    Posts
    12
    I've done some research on it and I have come to the same conclusion, I did come unhooked once and on "re-entry" heard a nasty high pitch whine come from what I think can only be the SC. However, having only done this once, I can't see it doing THAT much damage to the clutch? Without driving the 500 mile round trip to see James at 158 performance over here and asking him to have a look at it, I'm at a loss.. And ofc the fact that over here the cost of stuff is the same in £ as it is for you guys in $ the prop set me back the equivalent to $530 just a couple months ago

    Thanks again

    Tim

  5. #5
    SuperChief's Avatar
    Join Date
    Aug 2011
    Location
    Manchester, UK
    Posts
    12
    Right sorry troy, took me a while to type that post.. Trying not to sound stupid but, how do I check for leaks, by sound or feel or do I need a boost gauge? And I will ring the chap that fitted the prop tomorrow and find out.. I would imagine it to be a 20R prop as James knows his stuff but will check anyway

    Tim

  6. #6
    Mod less, ride more! troyheb's Avatar
    Join Date
    Jul 2007
    Location
    Nederland, Texas
    Posts
    8,725
    +1
    1,267
    Just grab hold of the hoses coming off of the SC going to the IC and to the TB and try and pull them loose. Some times the factory misses some clamps. My PX had a exhaust hose come off @ 3 hrs. If the clamps are not just right and you ride in rough water the hoses will come sometimes come loose.
    Also one other place to look is the coils. Take the white plastic cover off of the valve cover and see if any of the coils may have popped of the spark plugs.

  7. #7
    Mod less, ride more! troyheb's Avatar
    Join Date
    Jul 2007
    Location
    Nederland, Texas
    Posts
    8,725
    +1
    1,267
    Something else. There may be someone in your area who is a member here that would help out.

  8. #8
    SuperChief's Avatar
    Join Date
    Aug 2011
    Location
    Manchester, UK
    Posts
    12
    Quote Originally Posted by troyheb View Post
    Something else. There may be someone in your area who is a member here that would help out.
    I would love that to be the case, I really fancy getting into the engine work myself, just where to start??

  9. #9

    Join Date
    Jul 2007
    Location
    Montgomery, AL
    Posts
    257
    +1
    1
    I have an 08 RXT-X and the most I have ever seen is 8060 RPM on a cool day. If you were turning 8200 your wear ring must have been worn out and you were on the rev limiter. Your RPM's should be between 8000 and 8100.

    After sucking up a rocks to the point of needing a replacement prop I'd bet you dammaged the sharks teeth in the pump shoe. When they are dammaged they all need to be cut out and ground smooth or you will have a loss in performance.

  10. #10
    rxpsquad's Avatar
    Join Date
    Dec 2010
    Location
    birmingham UK
    Posts
    173
    Ok then do you have a blow off valve
    I just changed my prop yesterday on my Rxp
    And water tested it and was running 7400
    I took off the bov and changed the prop back to stock
    13/18 and my revs are back up to 8100
    Today
    Going to test again tomorrow with the 14/19 prop
    That should tell me if it was the bov
    So I would check the pipes from the super charger
    Or check your intercooler it might be leaking
    I see you are in Manchester so jet shed in Sheffield is closer
    To you than James bushell's place and Alan does know his stuff

Page 1 of 3 1 2 3 LastLast

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. NEW! Spark Seat Covers in stock and ready to ship!
    By Green Hulk in forum Sea Doo Spark
    Replies: 40
    Last Post: 01-19-2015, 03:07 PM
  2. Replies: 11
    Last Post: 07-19-2011, 05:41 PM
  3. RPM question first time out on green wheel and new prop
    By turbojamie in forum 4-Tec Performance
    Replies: 11
    Last Post: 08-08-2009, 07:10 PM
  4. Putting New Prop In And Everything Back Together
    By duramaxxed in forum 4-Tec Performance
    Replies: 8
    Last Post: 08-11-2008, 03:28 PM
  5. Prop pitches for max speed and performance
    By 2fast4u in forum Yamaha PWC Performance (2-stroke)
    Replies: 5
    Last Post: 11-05-2006, 01:48 PM

Posting Permissions

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