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New to Gopeds, odd issues, please help!

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  • New to Gopeds, odd issues, please help!

    Hi all,

    I recently bought a pre-owned goped sport that sat for many years. It has the zenoah g23lh engine, walbro 167 carb, high flow air filter, and a high performance muffler.

    I cleaned the carb, replaced the fuel lines, cleaned the air filter, and changed the spark plug. The thing rips, my phone has measured then speed at 22-23 mph.

    What's really odd is that when the fuel gets to about half tank, fuel doesn't seem to get to the carb and it barely runs. I basically have to keep the fuel tank full. Anyone know what this may be? I will add that when I was cleaning the carb I lost the tiny screen so the carb doesn't currently have the screen. Any ideas if that could affect the performance?
    Last edited by Newb; 05-09-2020, 09:29 PM.

  • #2
    Have you tried looking inside the tank to make sure the fuel filter is all the way at the bottom of the tank. Its a small black square attached to your fuel line inside the gas tank. Are you talking about the screen inside the black air filter box? If so no big deal if theyre not in there just make sure you have the foam


    • #3
      When I changed the fuel lines I made sure the fuel filter and the return line were at the bottom, right up against the tank just like the video on the goped website showed.

      The screen I lost when rebuilding the carb was in the carb and was tiny. It fell when I was trying to put it back in and disappeared. I don't think this affects anything since the screen is like an internal filter but thought I'd mention just in case.

      I'm fairly good at tuning the carb and have noticed that the only thing that affect performance is fuel level. Very odd. I've never seen this. Could it be that the carb needs a new diaphragm?

      Thx for the reply!


      • #4
        At this point I have no clue why it stops running at half tank. Thats pretty weird never heard that one before. The screen wont matter. Theres only a handful of people on this forum so it will be interesting to see if someone has an answer. Good luck brotha


        • #5
          That's what I'm thinking! Plenty of experience with 2 stroke but nothing like this. Fun as hell though, I'd just like to have a full tank of range. Thanks!


          • #6
            1) you need to determine that fuel level is actually your issue. If it is there are only 2 causes
            a)fuel filter/pickup is not at bottom of tank
            b)gas cap is not venting

            2)If both these are fine, fuel level is not your issue. these are not gravity feed carbs, they get their fuel via manifold vacuum.
            *******Pedding since '02********


            • #7
              In that case, it's not the fuel filter/pickup since that's for sure at the bottom.

              Interesting that you note the fuel cap; it had one of those nice billet caps (I believe ada) that wouldn't vent for the world. It had a hole but didn't vent. I took a cap off a weed wacker that had a type of foam vent. Is there a way to fix either one of these cap vents?


              • #8
                If theres a hole it should vent. I know most of the aftermarket fuel caps mention to use the gasket and filter from a stock gas cap. Dont think that should affect the venting though.


                • #9
                  The billet cap has a hole but then some odd gasket/one way valve too. Let me try and figure something out with the venting and I'll report back to you guys. Thanks!


                  • #10
                    A good cap should vent in only, not out. so be mindful of that.

                    A clogged vent will cause the Goped to die and not start, but removing and installing the cap will fix it issue temporarily.
                    *******Pedding since '02********


                    • #11
                      These were all great suggestions so here's what I did:

                      1. Removed one way valve on fuel cap and tested the goped. At half tank it still didn't run, at full tank it ran well.

                      2. Since the fuel filter was at an angle due to the factory hole being too low/close to the bottom of the tank; I removed the filter in the tank and added an on-line fuel filter. At half tank it still didn't run, at full tank it ran well.

                      3. After these steps, i ran the goped on a bench without a fuel cap. At half tank it still didn't run, at full tank it ran well.

                      ​​​​​​After all of this I said screw it and just went for a ride. What I noticed is that as the fuel level dropped, the performance also dropped... Very odd! I'm seriously thinking the diaphragm is suspect. I'd also like to add that the primer bulb runs pretty low on fuel, at times half full but never full. At times it looks entirely dry/empty.

                      Any thoughts?
                      Last edited by Newb; 05-11-2020, 07:55 PM.


                      • #12
                        check that the pulse holes line up on the carb. Next sto
                        ia just replacing the carb.
                        *******Pedding since '02********


                        • #13
                          I have no idea what a pulse hole is?

                          What would be a good replacement for a walbro 167a?

                          Is it normal for the primer to pump fuel right into the throat of the carb?


                          • #14
                            Primer bulb is there to just circulate fuel and remove air so that venturi effect can pull fuel into the carb once starting. Add pictures of "half tank" showing where the return and fuel pickup lines are. I would suspect that you have the return line on the bottom and pickup is actually near the top on accident.


                            • #15
                              I attached pictures of the tank where I drew a line at the point where it will no longer run and then another pic of the carb with the in/out lines shown. The inlet has a filter attached to it.