Results 1 to 10 of 10
  1. #1

    Join Date
    Jul 2010
    Location
    KC
    Posts
    478
    +1
    1

    2/3 and 3/3 break in with questions

    Breaking in a newly rebuild suv. Hi, I am finishing my breakin process today and new problem show up. While doing the 50% throttle for 30 min it when fine, then I did the 90%
    throttle and I notice one thing. While giving gas from 50% throttle to 90%. The engine is bogging like it is going to die. Then I let go of the throttle and then feather the throttle a few time and it will pickup running fine. The problem then "went away" after I got the throttle up to 90%. Increase and decrease speed with be smooth again. Until I shut of the engine and restart it again. And idea what should i adjust? The carb is in stock setting . I am using premixed 32:1 for break in, should I adjust the low and high speed needle and little?


  2. #2
    silvercrxsir's Avatar
    Join Date
    Sep 2011
    Location
    ocala,fl
    Posts
    334
    +1
    8
    Usually the low is just for idle adjustment and the high is for 90-100% throttle so the problem could be either in the jetting or the top end I would also check pop off pressure ,how long has it been since a carb rebuild and did you leakdown test it after reassembling everything.I would also check the compression to make sure that everything is breaking in properly and read the plugs to see how they look.another thing I would check is if the carbs has an accelerator pump and if its properly working that basically is a small pump that when u hit the throttle gives a little squirt of fuel to get it going.you can download a carbs manual from mikuni for free and it should have a section on carbs tuning that's very helpful for beginners.but if it ran fine on the old top end then u shouldn't have to mess with the jetting.I would start by lookin at the plugs to make sure it isn't going lean in a cylinder then compression test it to see how it is holding and check the accelerator pump if it has one

  3. #3
    silvercrxsir's Avatar
    Join Date
    Sep 2011
    Location
    ocala,fl
    Posts
    334
    +1
    8
    If it is the accelerator pump u can either rebuild it or re-jet to eliminate it I'm sure its been done on your motor and you could find what sizes you would need

  4. #4

    Join Date
    Jul 2010
    Location
    KC
    Posts
    478
    +1
    1
    Well, I rebuild everything. The carb the engine , pop off test pressure test, you name it. How I have been running the suv for three time now. Everything is fine except the bog down still happened. It only happened if I seat the suv long time also the mph goes to about 8 mph the bog down, I need to release the throttle and feather it a little. And it will run fine again. I read some post here seem like it is some water box problem. Need to feather to get the water out and then it run fine. Any thought?

  5. #5
    silvercrxsir's Avatar
    Join Date
    Sep 2011
    Location
    ocala,fl
    Posts
    334
    +1
    8
    Are you sure the low needles are set correct cause if it idles too long and is set too rich that could cause it to load up I've never heard of a waterbox issue I know on my gp800 the tube goes up around 8" higher than the waterbox to prevent water from getting in through the exhaust outlet I know when u rebuild the carbs it doesn't include the accelerator pump

  6. #6
    silvercrxsir's Avatar
    Join Date
    Sep 2011
    Location
    ocala,fl
    Posts
    334
    +1
    8
    If it only happens when u first start out it could be just cause the motor is cold i know when mine sits and I go to accelerate it will bog down but once it warms up its fine I know the water temp in the lakes here is still chilly so it takes longer to warm up does yours only do this when its cold

  7. #7
    silvercrxsir's Avatar
    Join Date
    Sep 2011
    Location
    ocala,fl
    Posts
    334
    +1
    8
    Also since u are finished breakin it in do a quick compression check and write the #'s down so u have a benchmark and you can track how the top end is wearing

  8. #8
    mudslanger's Avatar
    Join Date
    Jul 2010
    Location
    Huntsville Al
    Posts
    1,326
    +1
    49
    Quote Originally Posted by birdgod View Post
    Breaking in a newly rebuild suv. Hi, I am finishing my breakin process today and new problem show up. While doing the 50% throttle for 30 min it when fine, then I did the 90%
    throttle and I notice one thing. While giving gas from 50% throttle to 90%. The engine is bogging like it is going to die. Then I let go of the throttle and then feather the throttle a few time and it will pickup running fine. The problem then "went away" after I got the throttle up to 90%. Increase and decrease speed with be smooth again. Until I shut of the engine and restart it again. And idea what should i adjust? The carb is in stock setting . I am using premixed 32:1 for break in, should I adjust the low and high speed needle and little?
    You need to tune the carbs. Did you bore the cylinders what was done during the rebuild and what happened to it to have to be rebuilt just need a little history.

  9. #9
    silvercrxsir's Avatar
    Join Date
    Sep 2011
    Location
    ocala,fl
    Posts
    334
    +1
    8
    I'm sorry if I'm causing madness I do realize that the first issue is not your fault because I could have had a lean condition in the first cylinder but I did accept responsibility and replace the piston and yes I did have it honed by a machine shop and if it were a clearance issue in only the first cylinder I would have never even be upset but my problem is that the back cylinder which was totally fine never touched or honed is getting worse it had very slight scoring which I thought might have been an issue related to the front but since any fuel issue has been addressed and triple checked the rear cyl is only getting worse and is going to lead to piston failure.my main issue is that even if the front cyl never had an issue I would still be having this problem sorry if I'm causing grief and I will take better 360 views of the pistons and label them somehow so there is no mixups

  10. #10

    Join Date
    Jul 2010
    Location
    KC
    Posts
    478
    +1
    1
    The compression is 120 across. Ok, when I got the ski stared, it take a few minutes to warm up. Then it is running like new, throttle react perfectly. Then I shut it off to fish a little, for the rest 3 hours I start it up and move arround a little bit never when above 5 mph, during which time it start up prefect and moving around find. So the engine was never cold during that time. The problem the started when I about to leave. It start up right away, but when I give it throttle, it start to bog down at 8mph. then you know the story. But once I feather it to let it run smooth and it will continue to run good. Just want to be clear, the bog down does not alway happened, it only happened if I let it sit a little longer without gong high speed.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. FICHT break in with or without oil added
    By keithg1964 in forum Kawasaki PWC Performance (2-stroke)
    Replies: 23
    Last Post: 09-10-2013, 07:05 AM
  2. Ski check engine light on break in period question
    By djohnson44 in forum Sea Doo Open Discussion
    Replies: 11
    Last Post: 08-14-2012, 12:11 AM
  3. 1/3 break in with questions.
    By birdgod in forum Yamaha PWC Performance (2-stroke)
    Replies: 4
    Last Post: 04-07-2012, 04:49 PM
  4. Break-in oil question.
    By SpeedJunky in forum Yamaha PWC Performance (2-stroke)
    Replies: 5
    Last Post: 05-20-2008, 08:58 AM
  5. Break-in period question?
    By sakai in forum Kawasaki PWC Performance (4-stroke)
    Replies: 6
    Last Post: 09-09-2007, 09:27 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
  •