My 23 hp Kawaski on a 52" Wright Stander is hard to start. After cranking for about 30-45 seconds it will start popping and then it will fire. It will then smooth out and run fine. Once I turn it off and try to start it again it all happens again. If I install new RN11YC4 plugs it will start fine for about two cranks and then hard to start again. Removed and cleaned the carb several times. Installed all new gaskets, float, float valve. Took it to the shop and they said it was a clogged filter. They installed a new filter, pre-filter, and plugs ($85.00). Don't mind the price but it didn't work. Started the same thing again. Someone said the choke may not be closing all the way but I shouldn't need the choke after it is warm. Any suggestions?