I bought a second hand F20 a few months ago. It ran perfectly though it has always taken 6-7 pulls to get going. I have run Stabil Ethanol treatment through it since I got it Last week I went out to the driveway to run it because It had been nearly two weeks since I had started it. It would not start. Every 4th or 5th pull it would pop like it wanted to start, then nothing. I turned the carb drain screw and gas dripped out, so I knew it was getting fuel. After I did that it seemed more excited about starting, so I did it again after disconnecting the fuel hose. It finally started and ran flawlessly. I disconnected the fuel line and ran it dry. Yesterday when I got back from vacation I reconnected the fuel line. The fuel bulb was HARD. I couldn't compress it at all. Needless to say, It wouldn't start. I don't think I have a bad gas problem, because it runs great when it starts. The vent on the tank is open. The fuel filter is clean. Where should I start troubleshooting. Replace the fuel bulb or line?