Magnum MLT4000S — Adjusting the Valve Clearance
Adjustments · Engine valve train
For the Magnum MLT4000S, from the Magnum operator's manual.
Applies to: Magnum MLT4000S, Generac GN-220 engine
Procedure
- Ensure the engine is at room temperature and the piston is at Top Dead Center of its compression stroke with both valves closed.
- Loosen the rocker arm jam nut.
- Use an allen wrench to turn the pivot ball stub while checking clearance between the rocker arm and valve stem with a feeler gauge.
- When clearance is correct, hold the pivot ball stud with the allen wrench and tighten the rocker arm jam nut with a crows foot to 65-85 in-lbs (7-10 Nm).
- Recheck valve clearance after tightening the jam nut.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Valve clearance 0.001-0.003 inch (0.03-0.07 mm)
- Rocker arm jam nut torque 65-85 in-lbs (7-10 Nm)
Full service-parts list: Magnum MLT4000S →
Source: Magnum operator'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.