[Will98D]

My guess is that "the book" is so far off because the people that wrote it do know how to flow their carbs, but they intentionally give rich settings to prevent engine damage from running lean. It's basically like every snowmobile I've ever owned, they all come from the factory so rich that it's tough to get a day's riding in without fouling a plug. However, go too lean and spray molten aluminum around inside the cylinder. Usually, there's learning from the book to start, and then the improved learning that comes after with experience.