When you remove your air cleaner and look down the carb, you will see a round plate held to a shaft with a couple of screws. That is the throttle plate. One end of the shaft sticks through the carb and a cable is attached going to your gas pedal.Spray the shaft where it comes out of the carb and where your throttle cable is attached with WD40. I have never heard of WD causing sticking when warm. Try it. And do look for a return spring.If more help is needed you are at the right place......