Most of those kinds of problems are ethanol gas related. Congress decided we needed corn sugar in our fuel systems a few years ago and no none warned us of the consequences. Ethanol gums up fuel systems pretty bad and it only takes a few weeks of sitting to do it. Sometimes you can get by with running some Sea Foam in it, otherwise as Birken Vogt said, clean out the jets.
As a preventive measure, I only run non-ethanol gasoline in engines that may sit more than a month. If non-ethanol is not available in your area you could use aviation gasoline.
Adding fuel stabilizer to ethanol gasoline extends the life a few weeks, but I would not trust it to sit over the winter. For periods of 5 months or more, I use both non- ethanol gasoline and fuel stabilizer (like PRI-G).