Yes. Gasoline can gum up if left in the tank and evaporate in lines, leaving a residue. In addition, the carborator in your generator can also gum up if there is fuel left in it and it evaporates. I use a product called Seafoam which is a fuel stabilizer and cleaner. The cleaner more for the generator than the engine. It also keeps the fuel from evaporating and makes the generator easier to start.
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