Generac NP-30G / NP-40G — Adjusting Valve Clearance
Adjustments · Valve Train
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
Procedure
- Rotate crankshaft until piston is at TDC of compression stroke (both valves closed).
- Loosen the rocker arm jam nut.
- Turn the pivot ball stud with an allen wrench while checking clearance between rocker arm and valve stem with a feeler gauge.
- Hold pivot ball stud with allen wrench and tighten jam nut with a crow's foot to specified torque.
- Recheck valve clearance after tightening to make sure it did not change.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- GN190 valve clearance 0.001-0.003 inch
- GN220 intake 0.001-0.0022 inch, exhaust 0.0018-0.003 inch
- Jam nut torque GN190 75 inch-pounds, GN220 6.3 foot-pounds
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.