I've been attempting to get my tiller running, but I'm having trouble. The engine runs rough and then dies, and it must be kept with the choke on to run at all. I cleaned the jets, but that didn't help. When I removed the air filter, I could get it to run smoothly for awhile. I thought maybe the fuel is bad, so I drained the fuel. I put a fuel stabilizer in the tank after I finished last year. Fuel flows very slowly out of the tank. When I inhaled on the fuel line, after the tank was empty, there is a lot of resistance. The resistance appears to be in the shutoff valve. The line isn't blocked. I cleaned the filter in the shutoff valve, as well as the filter going into the engine. I'm not sure if fuel line resistance is normal on this engine. I'd appreciate some help in diagnosing and fixing this tiller.