I am wondering why blower carbs are different? I am talking about the ones that sit on top of a 6-71 or similar blower setup, not blow through carbs. It seems like they should work like any other carb by having a vacume pulled through them. Why do they need to be different? I allways see special model listed in catalogs, but have no idea why they are used. I know someone on this site will know the reason. Thanks for the education.