My crawler equipped with a non turbo 3.9 litre Cummins four cylinder lives far from electrical power. I can't easily plug it in to heat the coolant. Sunday morning it was about 5 degrees F. It started, but smoked a lot, even after a warm up period, it was sluggish, and smokey. I'm not sure it was skipping, but it took extra throttle to function. An hour after starting, it suddenly cleared up. My theory is ice crystals in the fuel filter. I feel that gelled fuel would not have corrected itself. Am I right? How would you prevent it?
Put some fuel conditioner with anti icing additive in the tank.
If you have enough return fuel it'll heat things up sometimes and get the filter warmed up and the fuel thinned out. Is it still #2 diesel? Treat it with some anti-gel and/or dump some winter blend in to thin it out. Is there a drain on the filter? Keep the tank full and filters fresh when it's cold. Or move farther south . Most people here don't even know there's winter blend or #1 diesel!
My Cat had the fuel line freeze at the shut off valve after running for almost an hour. I don't think small engines have enough flow in the return to thaw fuel lines.
Change fuel filters also
I'll add kerosene, and fuel conditioner. This weekend is expected to be warmer.