I once had an issue where the mower would die after an hour. Turned out to be bugs bleached almost transparent blocking the outlet of the tank. It was crazy that it was so repeatable, eg 1 hour of use no problem then cough cough died. After a few mins it could be restarted but would soon die again. Next day or next week you could again get an hour out of it. You would think that fuel sloshing about would make it unrepeatable. Tried changing all sorts of things like the coils incase insulation was breaking down when hot. Then someone suggested draining out the tank and that solved it. I was using a 20L Jerry can to store gas and I think bugs were getting into the nozzle then being flushed into the mowers tank when I filled up. Now store the nozzle in a plastic bag.