Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 22
  1. #1

    Join Date
    Nov 2006
    Location
    east end of long island
    Posts
    79

    Just rebuilt the carbs on a 1200 having a slight issue.

    Hi guys. I just rebuilt two sets of carbs on my 2000 ls2000 boat. One motor fires right up and the other is not sucking any gas to stay running. If i hold my hand over one of the carbs at a time while cranking the motor over i do see fuel going into the venturi. Another addition i did was install a dual fuel filter setup and installed a fuel bulb to prime the filters up. When i squeeze the bulb on the passenger side engine it's easy and the fuel squirts out of the return line back to the boats fuel tank with ease. The drivers side motor however is building pressure in the bulb, is hard to squeeze and the fuel is sort of slow coming out of the return "barb" right off the carbs fuel rail. I am not sure what the issue could be here. The carbs were comepletly cleaned in my ultrasonic, then sprayed with contact cleaner and blown out with my compressor so i am confidient nothing is or should be lodged in one of the carbs but i am a bit stumped here.


  2. #2
    Check your pickups from the tank. You could have something clogged in there somewhere.

  3. #3

    Join Date
    Nov 2006
    Location
    east end of long island
    Posts
    79
    Quote Originally Posted by tshank123 View Post
    Check your pickups from the tank. You could have something clogged in there somewhere.

    Yes i thought of that so what i did was used the known good fuel supply hose but still have the same issue. Its apparent there is some obstruction or something in one of these carbs i imagine. I am trying to decifer the most logical path as to determine where the obstruction lies .... Damn carbs lol

  4. #4
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    I'd try disconnecting the hoses (one at a time maybe) in between the carbs and see how the fuel flows. Maybe start by disconnecting the last carb's fuel supply hose, pump the bulb and see how the fuel flows. work you way back the first carb. you could do the same with the return hoses until you find the problem.

  5. #5
    Moderator OsideBill's Avatar
    Join Date
    Mar 2006
    Location
    United States
    Posts
    11,875
    +1
    30
    do you have a filter on backwards?
    it doesn't take very much pressure to push fuel through the fuel pumps in the carbs.
    are any of the orifices on the returns plugged? they are .020" diameter holes.

  6. #6

    Join Date
    Nov 2006
    Location
    east end of long island
    Posts
    79
    This is what i have done since my last post. I removed the rack of carbs from the motor and then connected the fuel feed line directly to the return line and squeezed the bulb with no isuues at all so that rules out a bad pickup and or clogged return. After that i removed the first carb with the idle screw, filled a jar with gas, installed a rubber line on the return barb and the primer bulb on the input side and placed them into the fuel jar. I tried to push fuel but the primer bulb again had resistance to the point where fuel pressure was built so high it was trying to spray out of the input barb and i had to clamp the rubber line down real hard. When i removed the clamp fuel sprayed out under pressure. I then disassembled the carb and looked for blockages and found none. I checked popoff presure and it came in at 24-25psi as the ls2000 is stock. When i disassembed the needle and seat side of the carb i saw fuel in there however i did not see any on the fuel pump side. I cant figure out what the heck is going on. I am going to disassemble the other two carbs and see what they look and function like.

  7. #7

    Join Date
    Nov 2006
    Location
    east end of long island
    Posts
    79
    Quote Originally Posted by OsideBill View Post
    do you have a filter on backwards?
    it doesn't take very much pressure to push fuel through the fuel pumps in the carbs.
    are any of the orifices on the returns plugged? they are .020" diameter holes.
    I checked the return pinhole with my pick and it appears to be clear and i blew air through it as well. The fuel filter is on correctly for sure.



    If i am able to pull fuel when my buddy turns the key and my hand is over the velocity stack doesnt that mean that the carbs are plumbed correctly and that they are assembled the right way?

  8. #8
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    So you can push fuel through the return and it comes out of the inlet?? If you can push through the return and not push through the fuel inlet then you must have the fuel pump check valves backwards somehow. Like they are on the wrong side or pump body is flipped backwards? Not even sure if thats possible.

    Or you have your return and inlet hose backwards. got any pics to share? Maybe we can point something out.

  9. #9

    Join Date
    Nov 2006
    Location
    east end of long island
    Posts
    79
    No i didnt try to push fuel from the return side to the inlet side. I tried to push fuel from the inlet to the outlet and nothing would happen. I will take some pics.

  10. #10
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    Quote Originally Posted by fosgate99 View Post
    This is what i have done since my last post. I removed the rack of carbs from the motor and then connected the fuel feed line directly to the return line and squeezed the bulb with no isuues at all so that rules out a bad pickup and or clogged return.
    Oh I see. I read this part wrong. I thought you were experimenting with pushing gas backwards through the system just to see what it would do. My bad. I understand what you're saying here now.

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. tuning the carbs on a 97 gsx 800
    By ultra150nc in forum 2-Stroke Performance
    Replies: 11
    Last Post: 04-25-2008, 08:24 PM
  2. Question about winterizing without the carbs on GP1200R
    By rehr0001 in forum Yamaha Open Discussion
    Replies: 4
    Last Post: 10-05-2007, 11:11 AM
  3. Rebuilt the carbs... Help
    By 00pro785 in forum Polaris Open Discussion
    Replies: 10
    Last Post: 07-18-2007, 10:43 PM
  4. rebuilding the carbs on a -98 xp
    By Swedie in forum 2-Stroke Performance
    Replies: 0
    Last Post: 07-18-2007, 05:08 PM
  5. Setting the timing on a 1200
    By wetherby in forum Polaris How To & FAQs
    Replies: 15
    Last Post: 12-03-2006, 08:45 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
  •