my carb has been actin up it will not idle unless you set the chock. when it idles with out the chock it back fires and you hear a knockin sound on the inside when it tries to idle.had some bad gas but put new gas in with seafome. runs good at speed just not at idle

 

rebuild/replace the carb.

 

if it runs with choke but not without its a dirty carb just give it a good cleaning strip it all out and use carb cleaner and a high pressure air jet to blow it all out , look through the jets to make sure they are not blocked and dont forget to clean the tank because thats where your problem began , if you have room you could fit an inline fuel filter to stop this happening again