Tools Needed

Spark plug socket · Carburetor cleaner spray · Adjustable wrench · Screwdriver set · Needle-nose pliers · Small wire brush

Quick First Checks

• Check that the fuel tank has fresh, non-ethanol gasoline
• Ensure the engine oil level is topped off to the correct mark
• Verify the blade or safety bail is fully engaged
• Inspect the air filter to ensure it is not clogged with debris
• Check for a loose spark plug wire connection

Repair Steps

• 1. Check and Replace Spark Plug

  Remove the BPR6ES plug using a 13/16-inch spark plug socket. Inspect for excessive carbon or electrode erosion and verify the gap is set to 0.028-0.031 inches using a wire-style feeler gauge.

  ⚠ Disconnect the spark plug wire entirely before servicing the mower deck or engine to prevent accidental activation.

• 2. Carburetor Bowl Flushing

  Locate the 10mm bolt at the base of the carburetor bowl and drain the contents into a container. If you see debris or cloudy fluid, the bowl needs to be removed and the internal passages cleaned with carburetor cleaner and compressed air.

  ⚠ Work in a well-ventilated area away from open flames, as gasoline vapors are highly flammable.

• 3. Test Ignition Spark Quality

  Use an inline spark tester grounded to the cylinder head bolt. If the light does not flash brightly while pulling the cord, the coil or kill wire is compromised.

  ⚠ Do not hold the spark plug wire with bare hands while pulling the recoil; use insulated pliers.

• 4. Verify Choke Flap Operation

  Remove the air filter housing and observe the choke plate while moving the throttle lever to the 'Start' position. The plate must be fully closed; if it stays open, adjust the throttle cable at the clamp screw.

  ⚠ Ensure the engine is completely cool before removing air cleaner components to avoid contact with a hot muffler.

• 5. Clean Pilot Jet Orifices

  Remove the carburetor from the intake manifold and use a piece of fine copper wire or thin monofilament to poke through the pilot jet opening. Flush thoroughly with solvent to remove microscopic blockages.

  ⚠ Take care not to damage the soft brass orifice walls with hard steel tools.

• 6. Check Flywheel Key and Timing

  If the mower hit a hard object, the flywheel key may have sheared, causing the timing to shift. Remove the blower housing and check that the flywheel keyway aligns perfectly with the crankshaft notch.

  ⚠ Use a flywheel puller; never strike the crankshaft with a hammer as it can warp the precision bearings.

Avoid These Mistakes

• ✕ Using an automotive-grade cleaner that eats plastic carburetor internal components
• ✕ Neglecting to replace the carburetor gasket, which leads to vacuum leaks
• ✕ Over-tightening the carburetor mounting nuts, which warps the flange
• ✕ Attempting to start the engine without a fully seated air filter element
• ✕ Ignoring the kill-switch wire for internal grounding faults

Prevent Recurrence

• Always use a quality fuel stabilizer like STA-BIL in every gas can
• Run the engine until it dies by shutting off the fuel valve at the end of the season
• Replace the air filter at least once per season to prevent rich-running conditions
• Change the oil with 10W-30 synthetic annually to reduce internal friction
• Keep the cooling fins clean of grass clippings to prevent vapor lock in the fuel lines