Front of air filter soaked with fuel

Fuel and Air Systems

  1. Sonny

    Sonny FBBO Gold Member FBBO Gold Member

    Messages:
    686
    Likes Received:
    214
    Joined:
    Jan 19, 2017
    Location:
    Florida
    Local Time:
    11:57 PM
    2FE027DB-9CE4-41E5-AB64-830F76C53EEF.jpeg All of a sudden today my engine started running very rich (I have an air fuel ratio gauge) over 55mph, bogged down and nearly quit, and the front of the air filter is damp and yellow with fuel. What could cause THAT? Stuck needle or float? Blown power valve? Too strong a squirter? Cheap fuel pump over pumping? Choke?
    It’s a new 650 brawler carb. Only happens during off idle cruise over 55mph. Also went from good afr .95 lambda down to .8 and less under off idle cruise for no reason. Engine Cut off when it dropped down to .7 afr.

    The car has been great for 2 weeks, then out of the blue, it bogged and barely idled to a stop and ran consistently rich. Sat 1 minute then drove off and it happened again several times over 55. Did fine at idle and under 55. Thoughts?

    This was the first 85 degree day since engine was built. I tuned the carb with temps less than 70 and also with a 160 degree thermostat. Should I put the 180 degree in it, let it get hot and re-tune it (primary jets) for summer temps? Engine runs at 160 typically, went to 195 today in traffic but came down quickly underway.
     
  2. HEMI-ITIS

    HEMI-ITIS STREETER

    Messages:
    9,339
    Likes Received:
    9247
    Joined:
    Dec 14, 2008
    Location:
    Long Island,New York
    Local Time:
    11:57 PM
    What PN# carb is that?? There are several.......
    What did you change when you tuned it?
    What timing curve are you using and how is it adjusted?
    What was the A/F when it was getting hot,was it lean?
    Do you have changeable air bleeds?
     
  3. Sonny

    Sonny FBBO Gold Member FBBO Gold Member

    Messages:
    686
    Likes Received:
    214
    Joined:
    Jan 19, 2017
    Location:
    Florida
    Local Time:
    11:57 PM
    Not sure of part number, brawler 650 with mech secondaries.
    Changes: Blue pump cam (cured bog) larger squirter (35), jets were spot on (in winter months) 70 primaries.
    16 initial, 34 total with MSD blue springs and small bushing.
    Never lean today when hot, just rich over 55mph part throttle cruise. No sign of vapor lock.
    Yes has air bleed jets.
     
  4. Badvert65

    Badvert65 Well-Known Member

    Messages:
    735
    Likes Received:
    377
    Joined:
    Oct 11, 2013
    Location:
    Brightwood, Virginia
    Local Time:
    11:57 PM
    check your float level. Could be too high, then higher fuel pressure from higher RPM (assuming mechanical pump) causes overflow, possibly out the vents. Just a guess. Not a power valve, that would leak out the bottom and all the time the engine is running.
     
    • Agree Agree x 4
    • Sonny

      Sonny FBBO Gold Member FBBO Gold Member

      Messages:
      686
      Likes Received:
      214
      Joined:
      Jan 19, 2017
      Location:
      Florida
      Local Time:
      11:57 PM
      I’ll recheck but fuel level was half way up the sight glass.
       
      • Agree Agree x 1
      • hangn0ut

        hangn0ut Well-Known Member

        Messages:
        513
        Likes Received:
        249
        Joined:
        Nov 16, 2015
        Location:
        Alta Loma Ca.
        Local Time:
        8:57 PM
        Splice in a fuel pressure guage and bring the rpm up to freeway speed and see what happens. I have 2 holleys on a tunnel ram. Was blowing past the needle and seat left and right. Was changing em out. First this bowl than that one. What I finally found was this little chrome cheapie fuel pressure guage I was using was reading 3 lbs light. So 7 psi was really 10 psi. What a be....ch.
         
        • Agree Agree x 2
        • Thanks! Thanks! x 1
        • beanhead

          beanhead FBBO Gold Member FBBO Gold Member

          Messages:
          3,582
          Likes Received:
          5367
          Joined:
          May 18, 2014
          Location:
          Wackyfornia
          Local Time:
          8:57 PM
          The mixture richening up some when the weather gets warm is normal, puking gas is not. Double check those float levels first, that's the easiest. It seems as though something's plugged or stuck, I would get a rebuild kit, disassemble the carb, and go through it...it's easy and that will either cure it or at least rule it out. If it persists with new parts look toward pump/pressure issues. Remember--just because the carb is new doesn't mean the internals haven't degraded, it could have been sitting on the vendor's shelf for a long time. My Demon sat for a long time and when I finally got the car running, the pump diaphragms leaked bad.
           
          • Like Like x 2
          • Agree Agree x 1
          • Lionized

            Lionized Well-Known Member

            Messages:
            1,610
            Likes Received:
            1076
            Joined:
            Mar 23, 2014
            Location:
            Vancouver Canada
            Local Time:
            8:57 PM
            I'll practically guarantee your primary needle and seat is blocked, which is causing fuel to back up and erupt from your vent tube at that rpm.
             
            • Like Like x 1
            • Thanks! Thanks! x 1
            • Agree Agree x 1
            • MoparLeo

              MoparLeo NRA PATRON LEVEL LIFE MEMBER

              Messages:
              443
              Likes Received:
              300
              Joined:
              Nov 24, 2015
              Location:
              Moreno Valley, So California
              Local Time:
              8:57 PM
              160 * is too low. Warm it up with 190 * beside whatever else you do.
               
              • Thanks! Thanks! x 1
              • Agree Agree x 1
              • PurpleBeeper

                PurpleBeeper FBBO Gold Member FBBO Gold Member

                Messages:
                4,188
                Likes Received:
                3003
                Joined:
                Mar 20, 2011
                Location:
                Chicago
                Local Time:
                10:57 PM
                I "think" lionized, badvert & others have this right. You have extra fuel getting into your carburetor primaries for sure. So, you either have a piece of dirt or something in the needle & seat keeping it from closing all the way (very common), your front float level is too high (most of the time you want fuel just to the very bottom of the sight glass), or your fuel pressure is so high it is forcing fuel past an otherwise good/clean needle & seat. Stock fuel pressure is about 5psi & at 7psi or so you can start having the issue you describe. HOPE THIS HELPS!
                 
                • Thanks! Thanks! x 1
                • Photon440

                  Photon440 FBBO Gold Member FBBO Gold Member

                  Messages:
                  8,050
                  Likes Received:
                  6097
                  Joined:
                  Mar 14, 2012
                  Location:
                  Surrey, B.C. Canada
                  Local Time:
                  8:57 PM
                  I thought of that one too, but he said he has a Brawler carb and Holley recommends fuel in the middle of the sight glass.
                   
                  • Like Like x 1
                  • PurpleBeeper

                    PurpleBeeper FBBO Gold Member FBBO Gold Member

                    Messages:
                    4,188
                    Likes Received:
                    3003
                    Joined:
                    Mar 20, 2011
                    Location:
                    Chicago
                    Local Time:
                    10:57 PM
                    I totally believe you & I've seen some people putting fuel levels up that high. I've always set my Holley floats so no fuel at all comes out at idle on a flat surface with the site plugs removed, but does spill a little bit when you shake the car....right at the bottom lip of that site glass hole.

                    If I had Sonny's car, I would start by changing out the front needle & seat. It's the most likely problem, cheap & can be done in 15 minutes.
                     
                    • Like Like x 1
                    • beanhead

                      beanhead FBBO Gold Member FBBO Gold Member

                      Messages:
                      3,582
                      Likes Received:
                      5367
                      Joined:
                      May 18, 2014
                      Location:
                      Wackyfornia
                      Local Time:
                      8:57 PM
                      Yes he definitely needs to confirm where the manufacturer wants the float levels for that carb. Demons are to be at one of the three middle lines while most of the holleys say just when fuel appears at the bottom..but some of the newer ones are different..
                       
                    • hangn0ut

                      hangn0ut Well-Known Member

                      Messages:
                      513
                      Likes Received:
                      249
                      Joined:
                      Nov 16, 2015
                      Location:
                      Alta Loma Ca.
                      Local Time:
                      8:57 PM
                      Never cared for that when the fuel just dribbles out. Whos to say that the dribbling is what keeping the fuel at that level? And when you put the plug in the level keeps rising? But thats the way I do it regardless. Now the clear site plugs, I have been told, can fail and fall out. A person in the industry whom I trust. Not the ones that come on some carbs but the replacement ones.
                       
                    • kiwigtx

                      kiwigtx International Mod Staff Member FBBO Gold Member

                      Messages:
                      15,551
                      Likes Received:
                      24400
                      Joined:
                      Jun 12, 2012
                      Location:
                      Tomorrow, NZ
                      Local Time:
                      4:57 PM
                      I hope you don't mean the Holley screw in clear sight plugs - they are meant only for tuning purposes...not designed for driving around the streets in. They are only plastic, and will likely fall out or melt under driving conditions.
                       
                    • Sonny

                      Sonny FBBO Gold Member FBBO Gold Member

                      Messages:
                      686
                      Likes Received:
                      214
                      Joined:
                      Jan 19, 2017
                      Location:
                      Florida
                      Local Time:
                      11:57 PM
                      Finally got around to checking out the carburetor. The float level was fine, fuel pressure 6lbs, and the needle and seat was also fine with no debris.

                      So I began to think what did I do in the past two weeks that could make the air filter wet with fuel. The only two things I did, was a. install the vacuum advance on the distributor, and b. removed the small pink pump cam and replaced it with the massive blue one and went from a 31 nozzle to a 35 chasing a bogg. I think “b” is the problem. I can remember actually hearing the pump shot hiss over the engine running when I hit the accelerator. I think it was giving me way too much light throttle pump shot over 55 miles an hour even at light throttle movements. I’m hoping that coupled with a 85 degree day caused the flooding.
                       
                    1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
                      By continuing to use this site, you are consenting to our use of cookies.