I recently acquired a Toro wheel horse 416-8 with the onan motor. First thing I did was change spark plugs, air filter, and fuel filter. Filled the tank with new fuel and a can of seafoam. It ran great for the first 30 minutes of use. Now it's struggling for fuel and there's hardly any fuel in the fuel filter. I checked the catch screen in the fuel tank and it's clean. Where should I go from here?