A healthy spark plug is the heart of a well-running small engine, and your Stihl leaf blower is no exception. A fouled, worn, or incorrect spark plug can lead to hard starting, reduced power, increased fuel consumption, and even engine damage. That’s why knowing the right spark plug for your specific Stihl model is crucial for optimal performance and longevity.
While always referencing your owner’s manual is the gold standard, this guide provides a handy “Stihl Leaf Blower Spark Plug Chart” to help you quickly identify the common spark plugs for popular models.
Why Spark Plugs Matter
Spark plugs ignite the air-fuel mixture in your engine’s combustion chamber. Over time, carbon deposits can build up, and the electrode can wear down, leading to a weak or inconsistent spark. This directly impacts your blower’s efficiency and overall health. Replacing your spark plug regularly, typically once a season or every 25-50 hours of operation, is a simple and inexpensive maintenance task that yields big rewards.
Decoding Spark Plug Codes (Briefly)
Spark plug manufacturers like NGK and Bosch use a series of letters and numbers to denote specific characteristics of the plug. While we won’t dive deep into every nuance, here are a few common elements you might see in Stihl blower spark plugs:
- Heat Range: This indicates how well the spark plug dissipates heat. A “hotter” plug retains more heat, while a “colder” plug dissipates it faster. The correct heat range is vital for preventing pre-ignition and fouling.
- Thread Diameter and Reach: These ensure the spark plug fits correctly into the engine head.
- Resistor Type: Many modern small engines require resistor-type spark plugs to prevent interference with electronic components.
Stihl Leaf Blower Spark Plug Chart (Common Models)
Below is a general guide. Always double-check your specific model’s owner’s manual for the most accurate information. Stihl often uses NGK or Bosch spark plugs as original equipment. You may also find compatible spark plugs from other brands like Champion, but cross-referencing is essential.
| Stihl Blower Model(s) | Recommended NGK Spark Plug | Recommended Bosch Spark Plug | Notes |
| Handheld Blowers | |||
| BG 45, BG 46, BG 55, BG 65, BG 85 | BPMR7A | WSR6F | Older models, check manual for exact match. |
| BG 56, BG 66, BG 86, SH 56, SH 86 | CMR6H | (Often equivalent to CMR6H) | Very common for newer 2-stroke models. |
| Backpack Blowers | |||
| BR 45, BR 320, BR 340, BR 350, BR 400, BR 420, BR 430 | BPMR7A | WSR6F | Older models. |
| BR 200, BR 500, BR 550, BR 600, BR 700, BR 800 | CMR6H | (Often equivalent to CMR6H) | Very common for newer 2-stroke models. |
| KombiSystem (KombiMotors) | |||
| KM 55, KM 85 | BPMR7A | WSR6F | |
| KM 56, KM 94 | CMR6H | (Often equivalent to CMR6H) | |
| KM 90, KM 110 | USR7AC | Specific to some 4-MIX engines. | |
| KM 130, KM 131 | CMR6H or USR4AC | Can vary, check manual. |
Important Considerations:
- Gap Setting: Always check and adjust the spark plug gap to the specification in your Stihl owner’s manual. An incorrect gap can lead to misfires or poor performance. This is typically 0.020−0.025 inches (approx. 0.5−0.65 mm).
- Genuine Stihl vs. Aftermarket: While aftermarket spark plugs can be a more affordable option, ensure they are high-quality and cross-reference correctly. Using genuine Stihl parts or recommended brands like NGK and Bosch is always recommended for optimal performance and to maintain your warranty.
- Four-Mix Engines: Stihl’s 4-MIX engines (which run on a fuel/oil mix but have valve trains like a 4-stroke) often use spark plugs with slightly different heat ranges or specifications. Pay close attention to your model if it’s a 4-MIX.
- Look It Up! The best and most accurate source for your specific Stihl leaf blower spark plug is always your owner’s manual or the official Stihl USA website’s parts lookup tool. You can also visit your local authorized Stihl dealer for expert advice.
When to Replace Your Spark Plug
Beyond the recommended service intervals, consider replacing your spark plug if you notice:
- Difficulty starting: Especially if it cranks but doesn’t fire easily.
- Loss of power: Your blower isn’t moving air as effectively as it used to.
- Rough idle or sputtering: The engine doesn’t run smoothly.
- Excessive smoke: While two-stroke engines produce some smoke, an unusual amount could indicate an issue, potentially related to the spark plug.
- Increased fuel consumption: You’re refilling the tank more often than usual for the same amount of work.
By using the correct spark plug and maintaining it properly, you’ll ensure your Stihl leaf blower continues to deliver reliable, powerful performance for seasons to come. Happy blowing!