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 I am very confused and pissed at TAOTAO FOR BUILDING SUCH JUNK. If anyone has a solution ,Please let me know. Is there a different carb all together that might work ?? A WEBBER or MACUNI. I'm willing to try anything . Maybe building a manifold for a lawnmower carb. HELP PLEASE
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.