It is rare that a diesel is good enough to start below 30 with out assist. Some need it more then others and won't start much below 40 or 50.
That's surprising. Our oldest, highest-hour diesels all start in the 20's.
40 or 50? If that were the case we'd have no time to repair or maintain anything...we'd spend all day going from jobsite to jobsite just to get stuff running!
That said, Perkin's stuff doesn't like the cold much at all. Without starting aids, they won't go much below 30. And while their fuel-dribbling-into-the-intake-to-light-a-fire system does work, getting unfamiliar users to properly perform the starting drill is a tough sell. Especially when everything else on site fires up without any special devices or instructions...