Trouble starting, manual choke. 2004 Zuma
 

Working on a 2004 Zuma yw50 and can't seem to get it to start consistently. At first I though it would only start with starter fuel, but I did not want to keep using that. Then I discovered it would start if I cover the intake with my hand and manually choke it. Stays running fine after that. Starts up right away after a minute, but if I let it sit for an hour Im back to square one. Ive cleaned the carb, tried replacing both fuel and vacuum lines, tested the petcock, new spark plug as well. What am I missing?

Stock air box? Stock jetting? Stock Pipe? So you have fuel and spark, how is compression? Sounds like an air mixture issue, too lean. Maybe up jet idle?