Background: Bought the unit a couple months ago after it had sit in repair shop for over 8 months. I got the unit started at shop and brought it home. I got all the green gas out of tank and cleaned it and replaced the filter. The unit would start and run(only ran it about 10min at a time) but I noticed that when the unit was on a slight hill with tank high the unit cut out. I took the carb off to see if it had green gas/water in it and cleaned with carb cleaner. After doingl that it started hard, but I got it going. Run okay still had cut out on hill. Unit sit for 7 days and I hardly got it to start again. I noticed that there wasn't much fuel in the fuel filter when stopped or when engine runs. The lines are all clean back to the tank. What is a good way to check fuel pump on this Kohler? Is it possible there are some diaphrams that dried out in the pump? I don't know much about this type of pump. ONe other question, should the gas cap allow air into the tank. I couldn't pull any air on either vent pipe with my mouth. Any help is appreciated.