1989 Geo Metro BaseFACTORY OEM SERVICE PROCEDURE

Remove, Overhaul & Install: Remove/Install/Overhaul: Introduction: Cleaning

  1. Thoroughly clean parts in carburetor cleaner. Dry components with compressed air. Blow out all passages with compressed air. Do not use wire or pointed metal objects for cleaning. Inspect air horn, main body and throttle body for cracks, breakage or scratches in sealing areas.
  2. Inspect choke and throttle shafts for wear. Check all jets and air bleeds for open passages. Inspect needle valve assembly for wear. Inspect float and pin for damage. Replace all damaged components.
  3. Inspect accelerator pump piston, all springs, strainer and pump injector for damage. Inspect accelerator pump piston bore for wear and scratches.
  4. Install spring and air vent solenoid on body. Apply 12 volts to solenoid valve. Check solenoid operation. Air horn assembly must be replaced if solenoid does not operate smoothly. Inspect air horn surface for distortion, scratching, and other damage. Replace if damaged.
  5. Using vacuum pump, apply vacuum to choke piston diaphragm unit. Assembly should maintain vacuum for a reasonable amount of time. Replace unit if vacuum is not maintained.
  6. Using ohmmeter, measure resistance between choke coil wire and housing. Resistance should be 1-11 ohms at 78°F (25°C). Inspect slow-cut solenoid valve and mixture by-pass solenoid valve body and spring spool for damage.
  7. Install slow-cut solenoid valve and mixture by-pass solenoid valves and spring on body. Apply 12 volts to solenoid valve. Check solenoid valve for smooth operation. Replace solenoid valve if operation is defective.
  8. Inspect diaphragm chamber. Push inward on rod of diaphragm chamber. Block hole of diaphragm chamber. Release rod and check that it does not move. Replace assembly if rod moves outward.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.