My sons jr 50 won´t stay on after I kick over. I completely cleaned the carb. I took apart and clean it well. All lines are good. Fuel cock good. Needle is good and float is fine. It starts up with starter fluid and has to be on choke. I put new plug as well. I am wondering if there is a fuel to air ratio and wondering how much fuel needs to be In the carb fuel bowl. I don´t see any coming out of the overflow. I need so help to get this 50 started. Oh one more thing, is there a fuel filter somewhere I am missing?