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Gas Spitting out the carb

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    Gas Spitting out the carb

    Hey all,

    I dug my 125 out of the snow bank the other day for a project I’m working on. Put in new fluids, swapped over a good starter generator, cleaned the fuel tank, cleaned the carb, set points, adjusted the valves swapped over coil and condenser from a good running machine. But it is still loading up and not revving up. When it try’s to rev it starts spitting and sputtering gas out the carb.

    I thought this would mean a timing issue but as far as I know I have that set right.

    Ive also read about burnt intake valves, not sure if that is what I should look into at this point.

    spark plug is covered in soot.

    Any thoughts?

    ill post some pics of the final project if I can ever get this thing to rev above idle.

    Side note.... carb is a Chinese knock off but, still doesn’t explain the spitting of fuel.
    Tanner
    Elk River, Minnesota

    #2
    Make sure the condenser is making good ground. That is a common problem.

    Otherwise, it sounds like the intake valve is either out of adjustment, not seating good, or it is sticking in the guide and not closing fast enough. On an engine that has sat s long time, a sticking vslve is very possible. I know you just adjusted the valves, but are you 100% certain you had the engine on TDC when you did? If the intake was stuck/ sticking when you set the valves, that would also throw off the setting.

    My gut says the condenser isn't making good ground..... check that first.
    ~Jonathan
    Oblong, Illinois

    Just because it's old, doesn't mean it's obsolete!

    I've got a lot of Cubs in the barn....but I have more implements/attachments!

    Comment


    • G-Nest
      G-Nest commented
      Editing a comment
      Thanks for the quick response! I’ll double check the valves/TDC.

      Also I’ll ensure the condenser is grounded. I think it is but didn’t realize that it needed to be. I’ll clean down to bare metal and re mount.

      Is a sticking valve guide something I can see from the side access hole on the engine, or does it need to come apart more?

    #3
    If gas is spitting out the carb, wouldn’t that mean the float isn’t set right? The engine won’t rev because it’s flooding out?
    Lance

    Cub Cadet, 73, 104, 106, 107, 125, 126, 127, 147 (2), 169, 1050, 1282, 1864

    Comment


    • G-Nest
      G-Nest commented
      Editing a comment
      It is spraying- like there is compression spiting/puffing it out, it’s not just like trickling.

      I’ll double check this today if I get a chance to get out there.

      Thanks!

    • J-Mech
      J-Mech commented
      Editing a comment
      Not usually Lance, although I understand your thought process.

    • sir_lancealot
      sir_lancealot commented
      Editing a comment
      👍🏼👍🏼

    #4
    First I cleaned up the ground on the condenser, that didn’t make any difference. Then I ran a ground jumper wire straight off the battery to the condenser... still no change.

    I re-set the timing this time with a volt meter and the flywheel marks as well as checked the valves.

    At this point I took off the head to see if I could see anything goofy going on, but not having many engines apart I’m not entirely sure what to look for... i didn’t see anything out of sorts, but I took a video if you care to look.

    The first part of the video you’ll see the symptoms and the gas spraying out, then the head off, then a close up of the valves after they were cleaned. Not sure this helps at all.... but sometimes it’s easier to show rather than me try to explain. 😁

    https://youtu.be/UwVa8rtmfhc


    Tanner
    Elk River, Minnesota

    Comment


      #5
      Where do you have the main fuel screw set?
      ~Jonathan
      Oblong, Illinois

      Just because it's old, doesn't mean it's obsolete!

      I've got a lot of Cubs in the barn....but I have more implements/attachments!

      Comment


        #6
        Two turns out, I’ve played with it and it doesn’t make much difference. Maybe its the Chinese carb haunting me? I’ve cleaned it a few times, but I can try swapping another onto it.

        I read somewhere someone was saying something about points wearing out, so I have a new set coming as well.

        For what I’m using it for I doesn’t need to come off idle, but it’s just really irritating that this is happening and I’m running into this wall...
        Tanner
        Elk River, Minnesota

        Comment


          #7
          Cleaned up carbon on the head and valves, swapped over a set of points, a clean walbro carb, and new governor linkage.... one of those items fixed it. She rips now.

          thanks all for your input. I’ll post a pic or two in another section later this week when I put it to work.
          Tanner
          Elk River, Minnesota

          Comment


            #8
            Probably could have just filed the old points and it would have fixed it. Had you done that??
            ~Jonathan
            Oblong, Illinois

            Just because it's old, doesn't mean it's obsolete!

            I've got a lot of Cubs in the barn....but I have more implements/attachments!

            Comment

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