I have a new to me Kubota M6040. it was hard to start a few times earlier this winter in my unheated barn, but it was never to far below freezing, a dose of power supply and 911 in the filters fixed that. but yesterday(40+ degrees out) I was using it to move snow around driveway and every 10 minutes running between 1000 to 1500 rpm not working it too hard it would start to sputter and stall. so im thinking it's pulling air, got water in the fuel, or there's still a bit of gell in a line some where. If any one has had a similar experience or knows of any diagnostic I could do to narrow down my hypothosis I'd greatly appreciate it. Before I bought the machine the lift pump was replaced, the water separator was bypassed and there was a badly patched hole in the fuel tank that I had plastc welded. I also hooked the water separator back up.