Generac — Test 35 - Check Valve Adjustment
Adjustments · engine valvetrain
From a Generac service manual covering: 4700, QuietPact 40, QuietPact 40 LP, QuietPact 40G, QuietPact 40LP. Check it applies to your exact model before use.
Applies to: Generac 4700, Generac QuietPact 40, Generac QuietPact 40 LP, Generac QuietPact 40G, Generac GH-220 engine
Procedure
- Adjust valve clearance with engine at room temperature, piston at TDC of compression stroke (both valves closed)
- Alternatively, position intake valve fully open to adjust exhaust valve, and exhaust valve fully open to adjust intake valve
- Loosen rocker arm jam nut; turn pivot ball stud with 8mm allen wrench while checking clearance with feeler gauge
- Tighten rocker arm jam nut to specified torque with crow's foot while holding pivot ball stud
- Recheck valve clearance after tightening to ensure it did not change
- Install new rocker arm cover gasket and reinstall cover with four screws; 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 clearance 0.001-0.0022 in (0.03-0.056mm)
- Exhaust valve clearance 0.0018-0.003 in (0.046-0.07mm)
- Rocker arm jam nut torque 72 inch-pounds
Full service-parts list: Generac 4700 →, Generac QuietPact 40 →, Generac QuietPact 40 LP →, Generac QuietPact 40G →
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.