Have you changed the fuel lines in the last few years? The ethanol gas will age neoprene lines faster than you'd believe. It's also rough on the fuel pump diaphragms, making the 'rubber' flake off the fabric. Then there's always the ills that it works on the carb itself... The float adjustment would be low on my list of possibilities, the needle & seat would rank higher. You might want to catch any fuel you can & see if you have neoprene granules in it. Good luck!