Two weekends in a row now needed towed back in. It starts great cold (needs choked), but after running a while, and shut off, it wont start...it tries to fire, acts like it might be flooded. eventually the battery dies. After last weekend, changed the plugs and fuel filter, it started right up this am, but after running and sitting an hour or so, it wont start. It almost starts, and oen time actually did, but as soon as I gave it some throttle, it died....any thoughts?