Disconnect the fuel hose, take the air filter off, pull the throttle return spring off and take the top of the carb off. Blow in the fuel inlet while working the brass valve/nut with your finger. If you can always blow through it, you need a new float valve. If pushing on the little button stops flow, you're looking at throttle spindle bushes. They're a bit more of a job to replace, but still do-able. Sure, EMPI carbs are known for being poorly made, but there's still a difference between one made on a Tuesday morning and on a Friday afternoon. It may well be fine, just needs a bit of a service.