Generac 4700 / QuietPact 40 — Adjusting Valve Clearance
Adjustments · Rocker arm / valve
For the Generac 4700 / QuietPact 40, from the Generac service manual.
Applies to: Generac 4700, Generac QuietPact 40, Generac GH-220 engine
Procedure
- Adjust valve clearance with the engine at room temperature.
- Position piston at top dead center of its compression stroke (both valves closed).
- Loosen the rocker arm jam nut.
- Use an 8mm allen wrench to turn the pivot ball stud while checking clearance between rocker arm and valve stem with a feeler gauge.
- Hold the pivot ball stud with the allen wrench and tighten the rocker arm jam nut to 72 inch-pounds using a crow's foot.
- Recheck valve clearance to make sure it did not change.
- Use a new rocker arm cover gasket, install rocker arm cover with four screws and install oil breather tube.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Intake Valve 0.001-0.0022 inch (0.03-0.056 mm)
- Exhaust Valve 0.0018-0.003 inch (0.046-0.07 mm)
- Rocker arm jam nut 72 inch-pounds
Full service-parts list: Generac 4700 →, Generac QuietPact 40 →
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.