Zenith 28 228 Carburetor

IDENTIFICATION

Zenith put a round aluminum tag on most carburetors located on the top of the carburetor. The number is stamped on the round tag

This carburetor had a secondary venturi which is pressed into the primary venturi.

The 28 228 is referred to as a'balacked' design in that all the air for the fuel bowl ventilation and idling must enter through the air cleaner.

Any restriction in the air cleaner will have an effect upon the fuel-air mixture ratio.

These carbs have single idle, main, accelerating, and power jets.

DIFFERENCE BETWEEN 28 AND 228 SERIES

The basic difference is in the idle circuit.

The 28 series has a single idle discharge plug in line with the closed throttle plate. The idle needle valve is located in the air intake body.

The 228 includes a two hole idle system with one hole located above the closed throttle plate and the other below the plate with the idle needle valve located in the throttle body.

MODEL IDENTIFICATION

28A: throttle shaft and choke shaft parallel
28B: throttle shaft and choke shaft crossed

MATERIAL

Air intake and fuel bowl are die-cast.

Throttle body is cast iron

MODEL LETTER DESIGNATION

P: packing or bushings in shaft holes

V: vacuum operated power jet valve

X: flange next size larger than standard

C: automatic choke control

D: equipped with degasser

R: built in governor

SIZES