Do you have a 28AV11 or a 228AV11.. can you tell?

[pfarber]

As I looked through the Zenith Operation and service bulletin Z-190-B for the eleventy-billionth time I notices a paragraph, more like a single sentence on the first page:

"The 228 Series carburetor is a modification of the 28 Series to us a two-hole idle system, and my be identified by the location of the idling adjusting needle in the throttle body.

Here's the good ole Series 28. Not that the idle adjustment screw is on the venturi and the throttle body inlet is a fixed port.

The Series 228 has this reversed:

Note the previous adjusting screw hole is closed with a rivet and the fixed port at the bottom is an adjustable screw.

Other than that one change the 28 and 228 are identical.. even the repair kits are the same.

[pfarber]

And of course my carb... it appears to have the correct 28 series top (the ID disk has the correct GM and Zenith numbers), but perhaps a 228 series bottom? I have not found enough info on Zenith carbs to figure the throttle body out.

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