Generac G0070420 — Adjust Valve Clearance
Adjustments · Valve train
For the Generac G0070420, from the Generac owner's manual.
Applies to: Generac G0070420, Generac GH-426 engine, Generac GTH-530 engine, Generac GT-999 engine
Before you start
- Allow engine to cool before adjusting valve clearance.
Procedure
- Make sure piston is at TDC of compression stroke (both valves closed).
- Remove spark plug wire(s) and position away from plugs.
- Remove spark plug(s).
- Remove the four screws attaching valve cover; remove and discard gasket.
- Loosen rocker jam nut (10 mm wrench 9-11 kW; 13 mm wrench 16-22 kW).
- Turn pivot ball stud (14 mm wrench 9 kW; 8 mm wrench 11 kW; 10 mm Allen 16-22 kW) while checking clearance with feeler gauge.
- Hold rocker arm jam nut in place as pivot ball stud is turned.
- When clearance correct, hold pivot ball stud and tighten rocker arm jam nut to torque spec.
- Recheck valve clearance after tightening jam nut.
- Install new valve cover gasket.
- Install valve cover; tighten fasteners in cross pattern to torque spec.
- Install spark plugs and torque to 18 ft-lbs (25 Nm).
- Reattach spark plug wire to spark plug.
- Repeat process for other cylinder if necessary.
Tools required
- feeler gauge Amazon
- 10 mm wrench Amazon
- 13 mm wrench Amazon
- 14 mm wrench Amazon
- 8 mm wrench Amazon
- 10 mm Allen wrench Amazon
- torque wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Jam nut torque: 9 kW 53 in-lbs (6.0 Nm); 11 kW 72 in-lbs (8.2 Nm); 16-22 FridayParts $66.30 kW 174 in-lbs (19.68 Nm)
- Valve cover torque: 9 kW 80 in-lbs (9.0 Nm); 11-22 kW 60 in-lbs (6.8 Nm)
Full service-parts list: Generac G0070420 →
Source: Generac owner's 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.