I have Tried everything to start these TaoTao 49 cc Mopeds. bypassed the vacuum activated gas petcock. Went straight from gas tank to carb. While plugging the open vacuum hose and petcock. It will start with hand choking or starting fluid. If i continue to use hand choking or starting fluid it will eventually run on its own. But after sitting for 15 min it wont start again. I bought two new carbs, no change. One moped has 10 miles the other has 50 miles.

Only because I thought that breaking them in might fix the problem of carburetor issues. It didn't.

If anyone has a solution ,Please let me know. Is there a different carb all together that might work ?? A Weber or Mikuni. I'm willing to try anything . Maybe building a manifold for a lawnmower carb.

  • Welcome to Motor Vehicle Maintenance & Repair! From you initial description, I'd suggest the carbs are at issue, but since you changed them, I'm a little stumped. Dec 14, 2018 at 13:15
  • Fuel tank orifice blocked? ie rubbish in tank...
    – Solar Mike
    Dec 14, 2018 at 13:40
  • Is there a mixture set screw? Dec 14, 2018 at 13:55
  • Do the carbs have a manual choke or primer?
    – rpmerf
    Dec 14, 2018 at 15:56
  • There are no adjustment screws , Except on the new ones there is a Horizontal screw at the bottom of the bowl Dec 15, 2018 at 18:19

3 Answers 3


It sounds like your carbs are running lean. The 'hand choke' making it run better verifies this. There should be a mixture screw. Carbs are not necessarily tuned from the factory. I've gotten carbs that wouldn't even start until I tuned them. Start by turning the mixture screw in until it bottoms out. Don't tighten it, just until it barely touches. Count the number of turns so you know where it was. Then back it out about 1.5 turns. This is typically a baseline. From there, try to start it and see how easily it starts, runs, and revs. Might need to pull it out further to get it to start. Work in half turn increments. If you have issues, go back to where it was initially, and work your way up from there. You do not want it running too rich, or you will waste fuel, dilute your oil, and cause excessive bore wear. You want to get it to where you can rev up the engine without bogging.

Some carbs need a special tool to tune the carb. I needed to buy a 'pac-man' tool to tune the carbs on my trimmer.

  • These carbs have no adjustments . No Screws Dec 15, 2018 at 18:14
  • Sorry there is a screw at the bottom of the bowl on the new carbs . It runs horizontal , dont know what it does. Dec 15, 2018 at 18:24

Hello all they do have an idle jet screw which has a steel plug covering it. You can remove the plug by either taking a eye glasses flat head screw driver and a small hammer and catching the edge of plug and bend it towards center of plug and work it out or drill a small hole in center of plug , insert a screw and pull with plyers


I found that by letting the engine run for 4 or 5 hours at various speeds , seated the rings. u can also drive it for awhile to help break in the engine. u follow out the plug running it on choke. also buying the 100cc kit eliminates all problems.

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