Results 1 to 4 of 4
  1. #1

    lean runaway after carb maintenance on 787

    Hi All,

    I posted this in the seadoo boat section without a reply, but this would apply to Ski riders too, so thought I'd post here too.

    Recently got the 96 Challenger out for it's first start up after a couple of months to get ready for Summer (Australia). Did the normal prep.
    Boat was stuck on full throttle, diagnosed the issue as a seized throttle shaft.
    I'm since removed the carb, fixed the issue and reinstalled the carb, without making any adjustments.

    Started it up for the first time the other day since putting it back together.
    Just on the trailer on a hose.
    Began to rev pretty high with throttle at idle position (5500rpm), thought it might just be from the dry carbs.
    Killed the engine.

    Decided while I'm at it I'll clean the Rave's, so did that also.

    Next day, started it up again; on the trailer on a hose.
    Didn't seem to rev as high, but still 4800rpm and sat there for about 2 mins before I killed it again. Stopped fine with stop button.

    So a couple of questions.
    Considering the Rev's seem to be dropping (from 5500rpm to 4800rpm between runs), is it merely a case of running it out on the water under load to allow the carbs to get a bit more fuel in to stop it running lean? Or is there anyway to prime them? Or is this unlikely to be the problem?

    When I cleaned the Rave valves I was unsure if I should grease up the gaskets. Could there be an air leak there?

    Finally, I destroyed one of the carb base gaskets between the intake manifold and carb when removing. I was unable to find stock of this gasket at local seadoo dealers.
    Being fairly mechanically inclined but new to Seadoo's, I made a new gasket from rubber and cork gasket material. But didn't grease either side of it.
    Am I looking at the most likely cause?

    Appreciate anyone opinions


  2. #2
    kecheme's Avatar
    Join Date
    Jul 2011
    Location
    Phoenix Az
    Posts
    208
    +1
    7
    Quote Originally Posted by cjb1985 View Post
    I made a new gasket from rubber and cork gasket material. But didn't grease either side of it.
    Am I looking at the most likely cause?

    Appreciate anyone opinions
    Cause: maybe your gasket clearance. When you torque down the carbs the rubber/cork is squeezed out and making contact with throttle blade.


    I'm taking a swag here but I recommend you find the oem carb gasket or make a better one. Use a paper type like a cereal box or stop by a auto parts store and ask for the universal paper gasket. In comes in a roll and different thickness I forget the exact name of it. Anyways cut out a better gasket lay it on the carb and check the clearance for the throttle blade and gasket, do this for each carb. Install carbs on motor and open throttle at carbs by hand, check if its smooth and returns freely. For now leave the throttle cable off and recheck your rpms.

    Report back with progress.

  3. #3
    Quote Originally Posted by kecheme View Post
    Cause: maybe your gasket clearance. When you torque down the carbs the rubber/cork is squeezed out and making contact with throttle blade.


    I'm taking a swag here but I recommend you find the oem carb gasket or make a better one. Use a paper type like a cereal box or stop by a auto parts store and ask for the universal paper gasket. In comes in a roll and different thickness I forget the exact name of it. Anyways cut out a better gasket lay it on the carb and check the clearance for the throttle blade and gasket, do this for each carb. Install carbs on motor and open throttle at carbs by hand, check if its smooth and returns freely. For now leave the throttle cable off and recheck your rpms.

    Report back with progress.
    Managed to get my hands on a WSM parts gasket, pretty much a clone of the original Seadoo gasket.

    She is starting perfectly, had a slight issue getting her above 2,500rpm once under load the other morning.
    Whilst limping back to shore, I gave the throttle one more squirt.
    Bogged a little, choked and spluttered but sprung to life.
    Straight to the plane and full speed in no time.

    Thanks for all your help

  4. #4
    kecheme's Avatar
    Join Date
    Jul 2011
    Location
    Phoenix Az
    Posts
    208
    +1
    7
    Quote Originally Posted by cjb1985 View Post
    Thanks for all your help
    Your welcome.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Replies: 2
    Last Post: 08-08-2013, 10:06 PM
  2. Lean Runaway Condition After Carb Rebuild
    By Arch-2012 in forum Yamaha PWC Performance (2-stroke)
    Replies: 23
    Last Post: 04-04-2013, 08:43 PM
  3. Lean Runaway kicking my *%&! on a 1200 non-pv
    By macGruber in forum Yamaha PWC Performance (2-stroke)
    Replies: 12
    Last Post: 09-15-2012, 05:10 PM
  4. lean runaway after carb maintenance on 787
    By cjb1985 in forum Sea Doo Sport Boats
    Replies: 2
    Last Post: 10-20-2011, 10:08 AM
  5. Carb Brace on 787 with Aftermarket F/A?
    By Team Bilford in forum 2-Stroke Performance
    Replies: 2
    Last Post: 07-14-2011, 10:34 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
  •