Your Stihl chainsaw is a powerhouse, a vital tool for any demanding task. But at its heart lies a small yet critical component: the spark plug. When it’s working flawlessly, your saw runs perfectly. When it’s not, you face frustrating starts and poor performance.
This guide will demystify the spark plug, explaining why the right one matters and how to use a spark plug reference to find the perfect match for your Stihl model.
Why Your Spark Plug is Crucial
The spark plug’s job is simple yet critical: it creates the precise electrical spark that ignites the compressed fuel-air mixture within your chainsaw’s engine cylinder. This controlled explosion generates the power to drive the chain. A healthy, correctly specified spark plug ensures:
- Effortless Starting: Quick, reliable ignition every time.
- Optimal Performance: Maximum horsepower and cutting efficiency.
- Superior Fuel Efficiency: Every drop of fuel is utilized effectively.
- Enhanced Engine Longevity: Reduces strain on your engine.
Conversely, a fouled, worn, or incorrect spark plug can lead to hard starting, misfires, reduced power, increased fuel consumption, and even engine damage.
Finding Your Perfect Match: Decoding Spark Plug Information
Stihl designs its chainsaws to work with specific spark plug types. While you might find aftermarket alternatives, sticking to the recommended Stihl-branded spark plugs or their direct OEM (Original Equipment Manufacturer) equivalents is always the safest and most reliable course of action. These plugs are engineered and tuned to Stihl’s precise specifications for optimal performance, efficient combustion, robust interference suppression, and a perfect seal.
Where to Find Your Spark Plug Data
The single most accurate and reliable source for your Stihl chainsaw’s spark plug information is your chainsaw’s owner’s manual. Stihl’s manuals invariably list the recommended spark plug(s) under the “Technical Data” or “Maintenance” section. This is your primary go-to resource.
If your manual isn’t readily available, you can also:
- Visit Your Local Authorized Stihl Dealer: They have direct access to the most current and accurate information.
- Check Stihl’s Official Website: Many manufacturers offer digital versions of owner’s manuals or comprehensive parts lookup tools online.
Representative Stihl Chainsaw Spark Plug Chart
IMPORTANT DISCLAIMER: This chart provides common spark plug recommendations for select, popular Stihl chainsaw models, serving as a representative guide only. Stihl produces a vast array of models, and specifications can vary by production year, regional market, and specific engine design. ALWAYS refer to your specific Stihl chainsaw’s owner’s manual for the definitive and most accurate spark plug recommendation and electrode gap for your exact model. Using an incorrect spark plug can lead to engine performance issues, damage, and potentially void your warranty.
| Stihl Chainsaw Series/Model (Examples) | Common Recommended Spark Plug (OEM/Equivalent) | Stihl Part Number (Common Example) | Electrode Gap (mm / inch) | Notes |
| 0-Series (Older) | Many older models share similar plugs. | |||
| 009, 010, 011, 015, 017, 018, 021, 023, 025, 029, 039, 041, 044, 046, 066, etc. | NGK BPMR7A or Bosch WSR6F | 0000 400 7000 | 0.5 mm / 0.020 in | Very common for many older 2-stroke Stihl saws |
| MS-Series (Modern) | Check manual for specific MS model variant. | |||
| MS 170, MS 180, MS 210, MS 230, MS 250 | NGK BPMR7A or Bosch WSR6F | 0000 400 7000 | 0.5 mm / 0.020 in | Popular homeowner & farm saws |
| MS 171, MS 181, MS 211, MS 231, MS 251 | NGK CMR6H (or similar) | 0000 400 7011 | 0.3 mm / 0.012 in | Newer generation with M-Tronic often use these |
| MS 260, MS 270, MS 280, MS 290, MS 310, MS 390, MS 361, MS 362, MS 440, MS 460, MS 660, MS 880 | NGK BPMR7A or Bosch WSR6F | 0000 400 7000 | 0.5 mm / 0.020 in | Covers many professional and larger saws |
| MS 261, MS 271, MS 291, MS 311, MS 391, MS 441, MS 461, MS 462, MS 500i, MS 661 | NGK CMR6H (or similar) | 0000 400 7011 | 0.3 mm / 0.012 in | Common for M-Tronic and newer pro models |
| Battery Chainsaws | N/A (No spark plug required) | N/A | N/A | MSA 160, MSA 200, MSA 220, MSA 300, etc. |
A note on spark plug codes (e.g., NGK BPMR7A): These alphanumeric codes indicate specific characteristics like thread diameter, heat range, design features, and whether it’s a resistor type. While useful for identification, the most important thing is to match the recommended plug part number from your manual to the one you buy.
Reading Your Old Spark Plug for Diagnostics
Once you carefully remove your old spark plug, its appearance can offer a wealth of diagnostic information about your engine’s internal health and running conditions. This process is commonly referred to as “reading the plug.”
- Ideal (Light Tan/Grey): Engine running optimally.
- Carbon Fouled (Dry & Black): Rich fuel mixture, too-cold plug, or restricted air filter.
- Oil Fouled (Wet & Oily Black): Oil in combustion chamber (worn rings/valves or incorrect fuel/oil mix).
- Overheated/Glazed (White/Blistered): Plug running excessively hot (lean mixture, ignition issue, too-hot plug). Serious, can damage engine.
- Worn Out (Eroded Electrodes): End of service life; large gap can cause misfires.
The Importance of Correct Spark Plug Gap
The precise gap between the center and ground electrodes must be set with accuracy for a strong, consistent spark.
- Check your manual: Always refer to your specific Stihl manual for the exact gap specification.
- Use a gapping tool: Never eyeball the gap. Use a dedicated tool to measure and adjust.
- Adjust carefully: Gently bend the ground electrode, avoiding damage to the insulator.
Essential Tips for Optimal Spark Plug Maintenance
- Regular Replacement is Key: Follow Stihl’s recommended maintenance intervals in your owner’s manual.
- Prioritize Genuine Parts: Opt for genuine Stihl spark plugs or their direct OEM equivalents.
- Maintain Absolute Cleanliness: Ensure the area around the spark plug hole is clean before removal or installation.
- Avoid Overtightening: Hand-tighten, then a small final turn with your wrench to prevent stripping threads or cracking the plug.
By understanding your Stihl chainsaw’s spark plug needs and performing regular maintenance, you’ll ensure your trusted machine continues to deliver reliable power and performance for every job you tackle.