Generator Valve Clearance Adjustment Guide

The intake and exhaust valve clearance should be inspected and adjusted if necessary every 300 hours of operation or once every 12 months, whichever occurs first.

Maintaining proper valve clearance ensures the engine runs efficiently and helps prevent premature engine wear.

⚠ Caution:
Incorrect valve clearance can cause:

• Hard starting

• Reduced engine performance

• Excessive engine noise

• Potential engine damage

Valve Clearance Specifications

Tools Required

• 8 mm socket wrench

• Spark plug wrench

• Feeler gauge

• Flathead screwdriver

Step-by-Step Valve Clearance Adjustment

Step 1: Remove the Spark Plug Cap

Pull the spark plug cap straight off the spark plug to disconnect it from the ignition wire.

Step 2: Remove the Valve Cover

Using an 8 mm socket wrench, remove the four valve cover bolts.

Disconnect the breather hose, then remove the valve cover to expose the rocker arms and valves.

Step 3: Remove the Spark Plug

Use the spark plug wrench provided with the generator to remove the spark plug.

Removing the spark plug allows the engine to rotate more easily when positioning the piston.

Step 4: Set Engine to Top Dead Center (TDC)

Insert a screwdriver into the spark plug hole to monitor piston movement.

Slowly pull the recoil starter rope until the piston reaches the highest position and both valves are closed.
This position is called Top Dead Center (TDC) on the compression stroke.

Step 5: Check Intake Valve Clearance

The intake valve is located on the right side of the cylinder head.

1. Insert a 0.005 in feeler gauge between the valve head and rocker arm.

2. Check the resistance.

Adjustment guidelines:

• If the gauge is too loose, tighten the rocker nut slightly.

• If the gauge does not fit, loosen the rocker nut.

The gauge should slide with light resistance.

Step 6: Check Exhaust Valve Clearance

The exhaust valve is located on the left side of the cylinder head.

1. Insert a 0.007 in feeler gauge between the valve head and rocker arm.

2. Adjust the rocker nut if necessary.

The feeler gauge should move with slight resistance but not bind.

Step 7: Reassemble the Generator

Once both valves are properly adjusted:

1. Reinstall the spark plug
   Torque specification:
   16.2 ft-lbs ± 1.5 ft-lbs (22 ± 2 N·m)

2. Reinstall the valve cover
   Torque specification:
   7.4 ft-lbs ± 1.5 ft-lbs (10 ± 2 N·m)

3. Reconnect the spark plug cap and ignition wire.

Common Questions

How often should valve clearance be adjusted?

Valve clearance should be checked every 300 hours of operation or every 12 months.

What happens if valve clearance is incorrect?

Incorrect valve clearance can lead to:

• Engine tapping or knocking sounds

• Poor engine performance

• Hard starting

• Potential internal engine damage

Why do I need to set the piston to Top Dead Center?

Setting the piston to Top Dead Center (compression stroke) ensures both valves are fully closed so the clearance measurement is accurate.

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✅ Support Tip:
Customers reporting ticking noises, hard starting, or loss of power after many hours of use may need a valve clearance inspection.