Generac IQ3500 — Valve Lash Adjustment
Adjustments · Engine valve train
For the Generac IQ3500, from the Generac owner's manual.
Applies to: Generac IQ3500, Generac GH-410 engine, Generac GT-530 engine, Generac GT-530 engine, Generac GT-990 engine, Generac GT-999 engine
Before you start
- Hold the rocker arm jam nut in place as the pivot ball stud is turned.
Procedure
- Engine should be cool before checking (60° to 80° F / 16° to 27° C).
- Remove spark plug wires and position them away from the plugs; remove spark plugs.
- Bring piston to Top Dead Center of its compression stroke (both valves closed).
- Remove the four screws attaching the valve cover.
- Loosen the rocker jam nut; turn the pivot ball stud while checking clearance with a feeler gauge.
- Correct clearance is 0.002-0.004 inch (0.05-0.1 mm).
- Hold the pivot ball stud and tighten the rocker arm jam nut to 174 in-lbs (19.68 N-m).
- Recheck valve clearance to make sure it did not change.
- Install new valve cover gasket and re-attach the valve cover.
- Install spark plugs and re-attach the spark plug wire.
- Repeat the process for the other cylinder, if necessary.
Tools required
- Feeler gauge Amazon
- 10mm Allen wrench (530cc engine) Amazon
- 13mm Allen wrench (410cc, 990cc, 999cc engines) Amazon
- Large socket and socket wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Valve clearance 0.002-0.004 inch (0.05-0.1 mm)
- Rocker arm jam nut torque 174 in-lbs (19.68 N-m)
Full service-parts list: Generac IQ3500 →
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.