Its not a hard job, just do it on a clean uncluttered surface. When you got it apart clean it all with carb cleaner, blow the jet out. Running with the choke on I would think would hurt performance because your not getting FULL air and gas tht the carb should deliver to the engine, and if your wrong and you do have an air leak somewhere you are running the engine lean and at risk of seizing the engine. You need to pull the plug and look at it. When you bought the kit did you clean the tank out? You might check the screen in the petcock inside the tank, that is the only filter, there is none in the carb. I would also get an inline filter so you can see when you have fuel flow. What are you running for an oil/gas ratio.