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Engine bucking/Return fuel line on mechanical pump

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  • Engine bucking/Return fuel line on mechanical pump

    Hi All,

    After my post last year about my rough & stumbling '54 Champion 6 cylinder engine I have pursued the mystery; to no avail. Reference:

    http://forum.studebakerdriversclub.c...TOPIC_ID=20602http://tinyurl.com/AirtexE8011Electricfuelpump
    http://tinyurl.com/HolleyPressureRegulator
    http://tinyurl.com/HolleySafetySwitch
    Henry Votel,
    Forest Lake, MN
    Buying & Selling Studebaker Parts in MN & WI

  • #2
    adjustment of the overdrive kickdown on the throttle linkage? Float level adjustment? Sometimes its just the driver. The car just doesn't like some people to drive it. Mabel my 49 champion does that to my husband. She runs just fine for me. Go figure.

    Mabel 1949 Champion
    Hawk 1957 Silverhawk
    Gus 1958 Transtar
    The Prez 1955 President State
    Blu 1957 Golden Hawk
    Daisy 1954 Commander Regal Coupe
    Fresno,Ca
    Mabel 1949 Champion
    Hawk 1957 Silverhawk
    Gus 1958 Transtar
    The Prez 1955 President State
    Blu 1957 Golden Hawk
    Daisy 1954 Regal Commander Starlight Coupe
    Fresno,Ca

    Comment


    • #3
      Hi Anne,

      Appreciate your thoughts.

      1) Overdrive wiring checked; overdrive kicks in fine. Stumbles/bucks in or out of overdrive. Once its in overdrive does that have anything to do with the throttle linkage? Hmmm.........not sure. Opine please!

      2) Float level set per Shop manual; have tried slightly different float levels; no difference. Have tried other carbs too.

      I'll be checking these again though after I hang the tank.

      Henry Votel,
      Forest Lake, MN
      Moderator: Editors & Publishers Forum
      Henry Votel,
      Forest Lake, MN
      Buying & Selling Studebaker Parts in MN & WI

      Comment


      • #4
        Henry, as you very well know, these cars are no where near as complicated as modern cars with all the computer circuits controlling "input" and "outputs" through oxygen sensors, fuel sensors, fuel injectors and who knows what other modules lurking under what part. I wonder if you have a tech school or other resource in your area that has a dyno. This would be a great candidate to place on a dyno so that you could investigate and trouble shoot the problem under load conditions. Except for that, It seems that you have covered all the bases you could With all the changing and trouble shooting you have done so far.

        John Clary
        Greer, SC

        Life... is what happens as you are making plans.
        SDC member since 1975
        John Clary
        Greer, SC

        SDC member since 1975

        Comment


        • #5
          Henry - I don't think you said, but now that the tank is out, have you pulled the sender so you can get a good look at the inside of the tank? I did this recently on my GT because I had a fuel delivery issue - the rust flakes and trash inside the tank were getting sucked against the pick-up, causing similar symptoms to yours. Just a thought...Russ Farris
          1963 GT Hawk R-2 4-speed
          1964 Avanti R-1 Auto

          Comment


          • #6
            Hi jclary & Russ Farris,

            jclary: Thanks for the attitude adjustment. I'm know I'm missing something. Will keep pursuing.

            Russ Farris: Yes, tank opened, drained, watched flexible wire go thru to end of the pickup tube. No trash in the tank. Blew gas line into a bucket; no trash their either. Fuel tank and line are clean.

            Will sleep on things tonight and get at it Sunday.

            Henry Votel,
            Forest Lake, MN
            Moderator: Editors & Publishers Forum
            Henry Votel,
            Forest Lake, MN
            Buying & Selling Studebaker Parts in MN & WI

            Comment


            • #7
              OK, I did NOT see where you said you did a fuel flow or pressure test at the fuel pump output! I have heard that the recent Mfg. Airtex 6 Cyl. fuel pumps have had low output issues because of a incorrect actuator lever stroke.
              There is a post on this issue somewhere.

              A gravity feed I.V. bottle direct to the Carb. like Matt Burnett has used, may prove that the little engine can run at a good RPM smoothly without bucking with no fuel pump, for testing. If you do this, just please, STAY AWAY FROM THE ENGINE FAN! OPERATE THE ENGINE FROM THE DRIVERS SEAT.

              Then if a good proven mechanical pump can not be found that provides a full stroke of the lever and a good fuel stream, then an Electric pump may be in order. I do not think a low revving small engine would require a fuel return system to prevent vapor lock using a correct original type fuel pump heat shield. If you were to install one however, it would definitely need a restrictor fitting like an Avanti to allow only a small return flow.

              Also the problem occurring when you let off of the go pedal, makes one wonder about the O.D. kickdown switch, one of it's jobs is to short out the Ignition points to cause the engine to hesitate to allow a no-load shift to O.D. if it had a [u]intermittent connection internally</u> or externally, I could see this happening. There is no electrical circuit operated by the O.D. shift handle to turn it off when out of O.D. so I don't know if it could still try to work even though O.D. is locked out.
              Try disconnecting and taping the wire from the distributor to the K/D Switch.

              StudeRich
              StudeRich
              Second Generation Stude Driver,
              Proud '54 Starliner Owner

              Comment


              • #8
                I'm make a suggestion. Disconnect everything from the coil and hot wire it straight off the battery. Drive and see if it makes a difference.
                In short isolating the engine wiring from the rest should make it easier to determine the cause. Doesn't sound like a fuel supply problem.
                I know you have changed distributor but could possibly have something to do with the vacuum advance.

                Comment


                • #9
                  I have vapor lock on these 93 degree days. The problem shows up as a bucking. Yesterday it was 100 degrees, the car would buck when I slowed down either for a traffic signal or when letting my foot off the accelerator to go slower on a down hill grade. Both situations cleared up quickly when I turned the electric pump on. I do think bucking can be a result of electric problems. Studerich's comments about the points shorting out with OD switch sound like a real possibility considering all the electric system checks you have done. Good Luck.

                  Comment


                  • #10
                    Hi StudeRich, leyrret and curt

                    The more I thought about this problem the more I was convinced I was missing something.....

                    Received a PM from the eminent J.R. about a similar problem he had encountered involving a bad intake gasket. I'd previously shot some penetrating oil at the manifold gaskets and not noticed any change in the engine idle.

                    After I got the gas tank on today I decided to go checking for vacuum leaks again. After starting the car and manifold not hot I really washed down the intake manifold and gasket with penetrating oil.....suddenly the engine started to idle better. Let it dry...it idled rough. Heavily washed again and it idled better.

                    Stopped engine, pulled the carb and manifold bolts, pulled the gaskets. Lower side of the gasket by two intake pipes were cracked on the gasket. Had one and replaced it. Bolted the whole thing back in place, (used liberal dose of anti seize on the threads in case I'm doing this again) and hooked up everything.

                    Started it----idled smoothly. Test drive----WOW it has never run this smoothly. Could not make it stumble/buck or kill when coming to a stop.

                    The problem is solved. Picked up my tools, Got cleaned up and showered. Had sex with my beautiful wife and will be going for a test drive later this evening.

                    It has become a great Studebaker day!

                    Henry Votel,
                    Forest Lake, MN
                    Moderator: Editors & Publishers Forum
                    Henry Votel,
                    Forest Lake, MN
                    Buying & Selling Studebaker Parts in MN & WI

                    Comment


                    • #11
                      quote:Originally posted by Henry Votel

                      The problem is solved. Picked up my tools, Got cleaned up and showered. Had sex with my beautiful wife and will be going for a test drive later this evening.
                      Great news, Henry...but, waaaaaay too much information!

                      BShaw, Webmaster


                      webmaster@studebakerdriversclub.com
                      Woodbury, Minnesota
                      sigpic
                      Bob Shaw
                      Rush City, Minnesota
                      1960 Hawk - www.northstarstudebakers.com
                      "The farther I go, the behinder I get."

                      Comment


                      • #12
                        I can see the headlines now...NEW CURE FOR E.D.!...A GOOD RUNNING STUDEBAKER!

                        John Clary
                        Greer, SC

                        Life... is what happens as you are making plans.
                        SDC member since 1975
                        John Clary
                        Greer, SC

                        SDC member since 1975

                        Comment


                        • #13
                          hmm, guess having sex and a test drive are NOT the same thing. I'm going to cut down on the test drives then.

                          '50 Champion, 1 family owner

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