Dump the gas, get fresh.
As for carb cleaner, get a can from NAPA or some such parts store and soak the carb but not more than 8 hours, marine carbs have a coating on them it will remove if left long term. Remove all gaskets, jets and plugs possible before soaking it, and if you have a kit coming then no big worries if you tear one up. Flush it out with hot water when you are done, use an air hose to blow out all passages and reassemble. Make sure your float heights are set right.
Idle is usually the first circuit to get gummed up on a carb, so you are on the right path.
Bufford
