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Zenith INAT Type 2-Barrel: Overhaul

Removal of carburetor is not necessary for minor overhaul and cleaning. Proceed as follows for on car overhaul. Remove center air cleaner stud, attaching bolts loosen tie rod lock screw and lift off carburetor cover. Remove idle jet and remove mixture block. Clean main jets (1), pump intake valve (2), pump pressure (3), and float chamber. Remove and clean air compensating jets (4), choke tubes (5), and accelerator pump piston. Air compensating jets and choke tubes, due to their different size, must go back exactly as removed. To replace entire choke housing, drain cooling system, remove sealing washer, pull off cables and water hoses and remove choke housing. When replacing choke housing be sure to line up notch on housing with notch on carburetor.

Fig 1: Accelerator Pump & Choke Tubes
G09313588Courtesy of NOT AVAILABLE
Fig 2: Choke Cover Installation
G09313589Courtesy of NOT AVAILABLE
CARBURETOR SPECIFICATIONS

Application Specification
Idle 900-950 RPM
Fast Idle 1800-2000 RPM
CO Level 1-1.5%
Float Level Setting (1)
Float Valve Gasket .04" (1.0 mm)
Float Weight .3 oz. (8.5 g)
Choke Index
  Butterfly Opening .118" (3 mm)
  Heater Filament 14.6V/.45A
Thermo Start Valve 20 ohm
Idling Cutoff Valve .13A/12V
Primary Circuit
  Main Jet x115
  Air Correction Jet 80
  Venturi 24
  Mixture Tube 6s
Secondary Circuit
  Main Jet x140
  Air Correction Jet 100
  Venturi 30
  Mixture Tube 4n
Idling Jet 42.5
Fuel Jet Thermo Start Valve 60
Accelerator Pump Piston
  Volume Injected Per Stroke .6-.9 cc
(1) Float level is determined by thickness of gasket under needle valve.