1950 Speeditwin Carburetor Leaking Fuel

Home › Forum › Ask A Member › 1950 Speeditwin Carburetor Leaking Fuel

Viewing 10 posts - 1 through 10 (of 33 total)
1 2 3 4
  • Author
    Posts
  • February 28, 2016 at 11:21 pm #3734
    viking66
    Participant

      Hi all,

      I got my 1950 Speeditwin all together and it is actually running.

      My main issue so far it that I have fuel coming out of the throat at rest, and it is spitting out when the engine is running.

      I was lucky to find this carb so I don’t want to mess it up. I am thinking the float may not be set correctly? Not sure because I cannot find any info about this carb other that the Operating Instructions.

      Advice and or service material on this would be Great!!!

      Thanks

      February 28, 2016 at 11:29 pm #32643
      crosbyman
      Participant

        Canada Member

        Did you service the carb…. ??

        the float must be adjusted to be level with the casing when held upside down.

        The float must FLOAT…. is it fuel logged ?? if so… dry it out sand lightly and recoat with crazy glue or airplane dope readjust to be parallel

        If the float is in bad shape… replace it

        do a blown test on the carb inlet fuel port before rebolting the carb

        right side up air goes in the fluel inlet
        upside down…. no air should pass the inlet needle

        visit Leroy’s web site for all sorts of articles

        Joining AOMCI has priviledges 🙂

        February 29, 2016 at 12:04 am #32653
        viking66
        Participant

          It seems to be floating I can see the pin mobe as it fills the bowl.

          I will check the level as you stated

          Leroy’s site??

          February 29, 2016 at 1:43 am #32660
          george-emmanuel
          Participant

            US Member

            First, the float in that carb is metal,–you cannot re-coat it. There is a slim, very slim, possibility it has a leak and is heavy, but that is extremely rare. If it is heavy from leaking, it need to be replaced. More than likely there is damage to the needle that allows gas to bypass it. Remove the needle and see if it has a smooth surface. You can smooth it using fine steel wool, but if it has grooves it needs a replacement. If it is good, turn the carb upside down and using a large pin punch and light hammer, lightly tap the bottom of the needle to seat it against the seat. Then see if it leaks on assembly.

            Speeditwin carbs are flame throwers! Wait till you see the flame it shoots out when it backfires without the front cowl on! And yes, they do spit a small amount of gas when running.

            George

            February 29, 2016 at 2:05 am #32662
            david-bartlett
            Participant

              The SpeediTwin carb is unique to say the least.

              Attachments:

              February 29, 2016 at 2:09 am #32663
              david-bartlett
              Participant

                You can see the float, needle, & seat in the above pics and their relationship. The pointed needle seats in the tapered portion of the seat and needs to fit properly to work right.

                February 29, 2016 at 2:38 am #32665
                viking66
                Participant

                  I got it checked out. Float is good and metal as stated.
                  The float is level. I did the leak test and it stops the airflow.

                  I may have been priming it to much. I have not re-worked an outboard with a carb like this, so a learning curve.

                  I did see the flame from a back fire, I was like what heck!!!

                  I will try again tomorrow, everyone went to bed early here so no more trying tonight.

                  I will post my results.

                  Thanks a bunch!!

                  February 29, 2016 at 3:00 pm #32673
                  crosbyman
                  Participant

                    Canada Member

                    ooops…sorry for wrong info I guess the date did not jump out at me… this is an old one…!

                    Joining AOMCI has priviledges 🙂

                    February 29, 2016 at 5:50 pm #32680
                    viking66
                    Participant

                      I think it may have been me and my heavy finger on the Primer…LOL

                      I only pressed it a few times today and it fired off pretty good.

                      Now to the fuel spitting out of the throat. Mine does this quite a bit. Seems a lot more fuel than should be coming out of there.

                      I went by my gut on how to set the speed control handle, and found about the low idle screw being 1 1/2 turns set from the factory, but I know nothing else of setting this Carb right.

                      Does anyone have reference material on this Carb? It would be nice to read over and see how it all works, and get it set up just the way it should be and maybe stop so much of the fuel from spitting out.

                      Thanks a bunch already :mrgreen: :mrgreen:

                      February 29, 2016 at 6:01 pm #32681
                      viking66
                      Participant

                        Belay my last!

                        I just re-read the Carb section of the Instruction Booklet.

                        I was in a hurry and missed all of the Great info there. As of now, no need for any further info.

                        Thanks

                      • Author
                        Posts
                      Viewing 10 posts - 1 through 10 (of 33 total)
                      1 2 3 4
                      • You must be logged in to reply to this topic.