Model 67 was built only in Zenith size 7 (SAE 7/8" nominal). More information on model 67-7.
Zenith model 267 and 73 carburetors were single barrel, updraft carburetors, ranging from Zenith size 8 (SAE 1" nominal) to size 10 (SAE 1-1/4" nominal). Model 267 carbs differ from the earlier 67 in the design of the economizer (power) system and idle systems. Model 67 carbs use a reverse idle adjustment, so that turning the screw in makes the mixture richer. In 267 carbs, turning the screw in makes the mixture leaner.
This series of carburetors was used on many different industrial and agricultural applications. The model 73 was a variant used on some IHC models. All versions use the same float, F9067.
Early carburetors had 4 screws connecting the float bowl to the throttle body, with the screws entering from the underside. Later model 267 carbs have an additional screw from the top of the carburetor to the float bowl.
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How to find Zenith carburetor numbers