Generac GT-760 / GT-990 — Adjusting Valve Clearance
Adjustments · engine
For the Generac GT-760 / GT-990, from the Generac owner's manual.
Applies to: Generac GT-990 engine
Before you start
- Do this only after first 50 hours of operation
Procedure
- Make sure engine is at room temperature
- Remove spark plug wire from spark plug
- Remove the four screws attaching the valve cover
- Rotate flywheel nut to bring piston to TDC of compression stroke (both valves closed)
- Loosen the rocker jam nut
- Turn the pivot ball stud with 10mm allen wrench while checking clearance with feeler gauge
- Set clearance to 0.002-0.004 inch (0.05-0.1 mm)
- Hold pivot ball stud and tighten rocker arm jam nut to 174 in/lbs torque
- Recheck valve clearance after tightening
- Install new valve cover gasket and re-attach valve cover
- Re-attach spark plug wire
- Repeat for other cylinder
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Clearance 0.002-0.004 inch (0.05-0.1mm)
- Jam nut torque 174 in/lbs
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.