[jeepguy1948]

Well Mike, when you are going downhill the fuel runs to the front of the bowl and creates fuel starvation but since you are going down hill you don’t need the fuel anyway (if engine dies while going downhill at idle that’s the problem). When you are going uphill there is a tendency for the carb but since now you are now going up hill and need the fuel, it works. I don’t know that it was designed that way but it seems to work out. A Zenith carburetor can bee a nightmare of won’t work right, won’t work right, won’t work right, and then boom, you finally find the perfect set up and it works great. I have a had problems with many Zenith carbs that were supposedly “rebuilt” by “professionals” and when I open them up, a thrown together mess. People swear that the Marvel Zenith replacement carb (from the Marvel Mystery Oil guy) is superior and easier to deal with. They aren’t hard to find. If you want to stay with an updraft carb but are not married to 100% stock/original that might be the way to go. Some Zenith bodies seem to be unusable after 90 years (of “Bubba” maintenance and abuse) and you have to try more than one to get a winner, that’s just the way it is.