You didn't mention the fuel you've been using, no one can give you a definitive answer without knowing. So what's up? Morgan? Don't worry about it, just flush everything out next year. Castor? A gummed up carb takes 15 minutes to clean if it sits 20 years, don't sweat it. Name the fuel and at least 10,000 members (or more) of RCU can give you the answer.