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NGK Spark Plug (BMR6A)

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NGK Spark Plug (BMR4A-SOLID)
A fouled or worn spark plug is often the first culprit when a Toro string trimmer won't start or runs rough. Since Toro trimmers use small gasoline engines designed to fire consistently, the spark plug has to deliver a hot, reliable spark cycle after cycle. Over a season of use — especially if you've left fuel sitting in the tank — carbon deposits and electrode gap growth will weaken the spark and leave you with a dead trimmer when you need it most.
Replacing your Toro spark plug is a straightforward five-minute job that costs just a few dollars and often restores full starting and running performance. The correct heat range and gap specification matter: too cold a plug and you'll foul it; too hot and you risk pre-ignition. Find your Toro string trimmer spark plug using your model number to ensure the exact OEM part and avoid compatibility guesswork.
Toro string trimmers typically use Champion or NGK spark plugs in standard sizes like RJ19LM or equivalent heat ranges. The correct plug depends on your specific Toro model — older models may differ from newer ones. Enter your model number on Repair Clinic to confirm the exact OEM spark plug specification. Using the wrong heat range will either foul the plug (too cold) or cause pre-ignition (too hot), so match the original.
Replace the spark plug at the start of each mowing season (spring for most users) and immediately if the trimmer won't start or runs erratically. If you run your trimmer year-round or use it heavily, check the plug every 50 hours of operation. A fouled plug from ethanol fuel is the #1 reason Toro trimmers refuse to start, and a fresh $3 to $5 spark plug is always worth trying before moving to carburetor repairs.
You can scrub the electrodes gently with a soft brass brush to remove carbon, then check the gap (usually 0.025 to 0.030 inch for Toro engines). However, if the plug is cracked, the electrodes are eroded, or it's been sitting unused for over a year, replacement is the better choice. A new OEM spark plug ensures consistent ignition and costs less than troubleshooting a persistent no-start condition.
Fouled plugs usually mean your carburetor is running too rich (too much fuel, not enough air) or your fuel is old and gummy. Ethanol-blend gasoline is a major culprit — it gels and leaves varnish that clogs the carburetor and dirties the plug. Use fresh fuel with ethanol stabilizer, run the trimmer until it empties at season's end, and if fouling persists, a carburetor clean or rebuild kit will likely be needed alongside the new spark plug.


Find the convenience of ordering Toro String Trimmer spark plug parts online. Ensure your weed eater runs smoothly with genuine OEM replacements, available for same-day shipping. Easily find compatible parts using model or part number lookup, and enjoy no-hassle 365-day returns with our Price Match Guarantee. Regularly replacing your spark plug can prevent your trimmer from stalling or running rough, keeping it in peak condition. Access our extensive repair resources to quickly troubleshoot and fix common issues like starting failures or rough operation. For additional repair assistance, visit our String Trimmer Repair Help page. Find more Toro String Trimmer spark plug parts to ensure long service life for your equipment.
Toro prints the model number on an identification label on the main housing near the engine or along the shaft. Check both areas, especially if dirt or wear makes the label hard to read, and copy the complete number exactly as shown, including letters. Enter it in the model number search to pull up the parts matched to your unit. The model number filters Repair Clinic's full Toro string trimmer catalog, so you can narrow every associated part to the versions designed for your specific trimmer, not just one part type. It is the quickest way to be sure the part fits before you order.

Regular spark plug replacement keeps your Toro String Trimmer starting cleanly and running at full power. Repair Clinic stocks OEM spark plugs for a wide range of engines, along with installation videos and gap-setting guides. Use the model number lookup to confirm the exact spark plug specification for your engine, and keep a spare on hand for the next tune-up.

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