Actually Lou, a professional mechanic was helping me clear snow today and said my Cat was acting like a newer Cummins that gets gummed up with carbon in the same kind of weather but my machine doesn't have any electronics. He suggested getting a new fuel filter and adding some fresh winter fuel. We've had some weird weather here, above freezing to -30C and then above freezing again.
Considering it needs fuel to run and a filter is routine maintenance, I don't think $10 or so is going to break the bank. Just in case I'll budget $30 in case I need some injector cleaner or more conditioner.