Thanks I will look at that tomorrow. It worked fine today. What really has me stumeped is it doesn't do it all the time. I have been plowing snow with it every day for 2 weeks getting tired of snow plowing.
The fuse can't be blown if it is an intermittent problem. Check it anyway since the fuse contacts could be corroded if they salt your snow.
The solenoid should have a connector to it that routes to the delay relay. Next time it doesn't shut off you may want to disconnect the wire at the connector. If that shuts off the engine then it is the relay. If not, then it is the solenoid. Neither are cheap to replace.
It could be something as simple as the fuel shut off lever on the solenoid is hanging up or debris is keeping it from actuating.
How do you shut it off when it won't do it by the key?
Or, you could just let it run and plow snow 24/7. There seems to be enough of it in your area. Your neighbors would be appreciative.