If you can plug it in, then why not.

Consider that:

Each compression cycle without combustion is un-burned fuel to contaminate the oil or dry the cylinder walls before the next stroke.

Harder cranking is higher current, faster brush/commutator wear in the starter.

Running rough/uneven is also washing the cylinder walls down with fuel and creating more soot for the oil.

And most important: plugging it in will give faster heat from your heater.

Even if it doesn't **need** to be plugged in, it certainly is easier on the engine, I plug mine in below about 45F just because I like those summertime instant starts (and because there's a plug in the garage for it).

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Gone to the dark side

- Jeff