Results 1 to 9 of 9
  1. #1
    Legend in my own mind Sirhc7897's Avatar
    Join Date
    Aug 2005
    Location
    Lake Butler, FL.
    Posts
    1,140

    Need Help diagnosing problem

    Well after my motor blowing a head gasket this time last year and then me breaking my shoulder in a ATV accident I was finally able to get the ski back together and on the water today for a little bit (damn that felt good).....

    All seems well enough (still chasing various little bugs) but I have the following problem:

    -Will be riding along and the ski would start stumbling and almost die out only to either come out of it and race back along at 8000-8050 or drop down to idle and after idling for a second or two get back to normal.....It did this a few times and then finally on the last time the ski wouldn't rev past 7600r's....

    It's got metal washers so I'm not suspecting that as a problem but it does feel as if it's only running on 2 cylinders at WOT when it does this. However idle is smooth and acceleration is crisp.

    Could I have a coil going out/gone out at higher rpms or should I possibly be investigating fuel delivery?

    Anybody else ever experienced this that can give me some guidance?

    My first thought was motor (since I reassembled it) but everything there appears fine. Compression is within a few psi of each cylinder, timing seems fine, etc....Valves and valvesprings are brand new, etc....It was a little high on oil but I was attributing that to the initially low overall rpms...not the sudden loss of 400?


  2. #2
    JFizzleJR's Avatar
    Join Date
    Aug 2005
    Location
    FL
    Posts
    8,628
    +1
    808
    Could be bad coil, plugs, leaking intercooler. Others will chime in.

  3. #3
    Legend in my own mind Sirhc7897's Avatar
    Join Date
    Aug 2005
    Location
    Lake Butler, FL.
    Posts
    1,140
    IC is good. Pressure tested that when I was putting it all back together. Plugs are brand new.

    Next weekend I'm going to hot swap my coils for my buddies and see what happens...My thoughts are coils or fuel related at this point but leaning towards a bad coil as it felt like a cylinder was dead. It's hard to describe but if you've ever only run on 2 cylinders you know the feeling I'm describing...

  4. #4
    speedskixp's Avatar
    Join Date
    Feb 2008
    Location
    venice fl.
    Posts
    8,117
    +1
    120
    I had a similar problem and it turned out to be my battery. Even though it would turn over fine and start it was causing a misfire and stumble.

  5. #5
    JFizzleJR's Avatar
    Join Date
    Aug 2005
    Location
    FL
    Posts
    8,628
    +1
    808
    Yes, I've ran on 2 cylinders It didn't go quite as nice as you describe though.

  6. #6
    Legend in my own mind Sirhc7897's Avatar
    Join Date
    Aug 2005
    Location
    Lake Butler, FL.
    Posts
    1,140
    Quote Originally Posted by speedskixp View Post
    I had a similar problem and it turned out to be my battery. Even though it would turn over fine and start it was causing a misfire and stumble.
    Battery is a brand new Riva as well......

    I'm hoping it's going to turn out to be a coil that's misfiring at max rpms...

    I was experiencing a very slight misfire at idle as well...

  7. #7
    captain obvious Lurker's Avatar
    Join Date
    Jul 2005
    Location
    Visalia, Ca
    Posts
    2,316
    How is your gas, bad gas can cause the same thing

  8. #8
    Prohibido usuario
    Join Date
    Aug 2005
    Location
    Jerry's guest bedroom
    Posts
    3,469
    +1
    2
    Yeah bad gas can cause a stumble at higher rpm's but at lower rpm's everything will seem fine.

  9. #9
    Legend in my own mind Sirhc7897's Avatar
    Join Date
    Aug 2005
    Location
    Lake Butler, FL.
    Posts
    1,140
    Very well could be gas...

    There was 2 notches of old gas (been in there since April). So I topped the tank off with fresh 93. I also added some seafoam to the oil and gas as my plan was to run through this tank and maybe one more to clean it all up and get it running right again after sitting so long and then do a oil change.

    Could bad gas be the culprit to it only running 7600rpms as well? I wouldn't think so?

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. gp1200r has no power, need help diagnosing the problem
    By kyle5647 in forum Yamaha PWC Performance (2-stroke)
    Replies: 6
    Last Post: 08-05-2013, 11:11 PM
  2. Need help diagnosing problem
    By grober02 in forum Kawasaki PWC Performance (4-stroke)
    Replies: 3
    Last Post: 08-01-2011, 06:43 PM
  3. I Need Help Diagnosing A Problem..
    By mikefeliz7 in forum 2-Stroke Performance
    Replies: 22
    Last Post: 02-17-2009, 06:29 PM
  4. New and need help diagnosing my '08 rxtx
    By dr_hunt in forum 4-Tec Performance
    Replies: 50
    Last Post: 06-28-2008, 06:16 AM
  5. Need Help, RXP problems, Plug pictures
    By Water4fire in forum 4-Tec Performance
    Replies: 32
    Last Post: 04-26-2007, 10:38 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
  •