check for kinks in the fuel lines..also might be a good idea the pull off carbs completely..inscrew the float bowels and inspect and clean them...also the stub hose that hanggs of the bottom of the bowl used carb cleaner and spray out the orafis holes...U would not beleive the buildup U will get in there from one year to the next..I doubt the gas stabilizer is bad...I used same bottle for several years on boat mtrs