Results 1 to 9 of 9
  1. #1

    Join Date
    Jun 2012
    Location
    McCalla, Alabama, United States
    Posts
    46

    99 GP800 Flooding

    At the end of the season last year, my friends GP800 started flooding out the front cylinder. Over the winter, he rebuilt both carbs and now the front one continues to flood. Any suggestions? He took them back off last night to inspect and visibly can't see any reason for this to happen. Any help or ideas would be appreciated.


  2. #2
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    When does it flood out? Idle? Cruise? WOT? All the time? Only when its not running?
    What makes you think its flooding?

  3. #3
    I wanna go FAAAAASTer!! CDW78's Avatar
    Join Date
    Mar 2010
    Location
    Ky
    Posts
    543
    +1
    6
    I was just reading on this topic today as a matter of fact, needle & seat is what the prob was. Most hadnt replaced those parts in the carbs.....

  4. #4
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    That's what I was thinking too

  5. #5

    Join Date
    Jun 2012
    Location
    McCalla, Alabama, United States
    Posts
    46
    Floods all the time and they replaced the needle and seat when they rebuilt the carb. I am inclined to believe that there are only a few components that could make it get too much fuel. Needle/seat or the lever/spring assemble above the N/S...

  6. #6
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    Yeah, almost has to be the NS or the lever arm is holding it open.

  7. #7

    Join Date
    Jun 2012
    Location
    McCalla, Alabama, United States
    Posts
    46
    Cutlass - thanks for the help, you've helped me with some trouble shooting before and I really appreciate it.

  8. #8
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    You're welcome. Hope you guys get it straightened out!

  9. #9

    Join Date
    Jun 2012
    Location
    McCalla, Alabama, United States
    Posts
    46
    Come to find out, it had zero compression on one cylinder. Looks like it has dropped a power valve. Time to rebuild the top end and see if that makes a difference.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. WTB '99 GP800 Drive shaft AND Impeller ASAP!
    By ProXR 440 in forum Yamaha Classifieds
    Replies: 4
    Last Post: 07-16-2008, 05:47 PM
  2. WTB!! Servo motor for 99 GP800!
    By CustomGP800 in forum Yamaha Classifieds
    Replies: 1
    Last Post: 07-14-2008, 01:58 PM
  3. '99 GP800 Probs
    By howestek in forum Yamaha Old School Skis
    Replies: 1
    Last Post: 09-15-2007, 07:25 PM
  4. 99 GP800 lost a cylinder
    By johnsonmtz in forum Yamaha Open Discussion
    Replies: 0
    Last Post: 07-23-2007, 09:51 AM
  5. 99 gp800 lost all power, 5mph tops, help me
    By lifted99f250 in forum Yamaha PWC Performance (2-stroke)
    Replies: 3
    Last Post: 07-03-2007, 01:43 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
  •