Facts About Generators
GeneratorsDirectoryCompareRepairEnginesControllersPartsManufacturersGuides
Search models or part #
Home›Repair guides›Generac›Carburetor Adjustment (Idle Jet)

Generac NP-30G / NP-40G — Carburetor Adjustment (Idle Jet)

Adjustments

For the Generac NP-30G / NP-40G, from the Generac service manual.

Applies to: Generac NP-30G, Generac GN-190 / GN-220 engine, Generac GN-190 or GN-220 (see NOTE 2) engine, Generac GN-220 engine

Before you start

  • Do NOT adjust the fuel-air mixture excessively lean; can result in engine damage.

Procedure

  1. Turn the idle jet inward (clockwise) until it just contacts its seat; do not force.
  2. Turn the idle jet outward (counterclockwise) 1-1/8 turns.
  3. Start engine and let it warm up about five minutes.
  4. With engine at no-load, turn idle jet clockwise (leaner) until speed decreases or fluctuates.
  5. Turn idle jet counterclockwise (richer) until speed decreases/fluctuates or black smoke appears.
  6. Very slowly turn idle jet clockwise until speed just stabilizes or black smoke just stops.

Specs & values

  • Initial idle jet setting 1-1/8 turns out
  • Factory altitude 900 feet above sea level

Full service-parts list: Generac NP-30G →

Source: Generac service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

More Generac repair guides →