Spark plugs are a key part of maintaining a petrol power tool, especially STIHL chainsaws, and you may think that one spark plug is much the same as another. A standard NGK spark plug and NGK spark plugs sold by STIHL may have the same part number stamped on them, but the STIHL NGK spark plug has some key differences.
The main differences between the STIHL NGK spark plug (right) and the off the shelf NGK plug (left) are:
- The union nut (1) of a STIHL spark plug is fixed in place. This ensures there is no spark gap which could impair performance or potentially ignite gasoline fumes.
- Interference suppression resistance (2) is tuned to STIHL machines for the optimal spark and efficiency. This protects the machine’s ignition module from early failure.
- STIHL spark plug sealing ring (3) is coated for a better contact and corrosion resistance, given that these tools are used in challenging and often wet environments.
- The electrode gap (4) is aligned to STIHL products for optimal compression.
For the best performance from your STIHL tool, we recommend that you always use the STIHL NGK spark plug.
The spark plugs are listed in the “Technical data” chapter of your machine’s Instruction Manual. For more information and to order your genuine STIHL spark plug, contact your local Approved STIHL dealer.
I need 2 R10 Spark plugs (1spare) for my long reach hedge trimmer
Hi John, thanks for your comment. We don’t sell any spare parts directly, so we recommend that you speak to your local STIHL Approved Dealer to order the part. You can find your nearest one here: https://shop.stihl.co.uk/pages/dealer-locator
Thanks, STIHL GB
NGK makes plugs with the same part number that are different? I am skeptical.
Hi, thank you for your comment. We understand how there could be some confusion, which is precisely why we wanted to write this blog post, with clear pictures showing and explaining the differences. Thanks, STIHL GB
Ok guy’s you have outlined the differences and you say both companies use the same part number.
So when I’m handed a Stihl NGK spark plug in the shop will it say Stihl on the box and is the plug it’s self stamped with the Stihl logo?
Hi, thanks for your comment. Once they are out of the box, there isn’t anything to obviously identify it so the best option is to make sure you ask for an official STIHL spark plug from a STIHL Approved Dealer. Thanks, STIHL GB
I’ve a 028 Wood Boss saw. I’ve been going through coils like crazy. A friend said that I should measure the resistance of the spark plugs in my collection. I just found a NGK. It had much high resistance than the rest.
Today, I put a nee coil in it. The saw started, ran pretty good but seemed as if the H carb setting needed a tweek. By the time i got the screwdriver, the saw died, not to be started again.
I called a technician friend. He suggested testing spark plug resistance. All my plugs except one were low ohms. The plug in the saw was one of them.
Is this the reason I’ve been having coil failures? Going to try that NGK tomorrow.
Hi, thanks for your comment. We recommend that you speak to a STIHL Approved Dealer to make sure that you get the correct STIHL spark plug as not all NGK are the same as STIHL NGK. One of our Product Experts has also said that they believe the older 028 Wood Boss saws had a different ignition coil so your dealer will need the serial number of your saw to confirm the correct part. I hope that helps, thanks, STIHL GB
Has a more proper or upgraded spark plug been introduced to the MS 462 c-m since the owner’s manual was created? I get conflicting and convincing input that the best spark plugs to use is the ngk cmr5h for the higher heat rating (it seems that the 5h is a hotter rated plug than the 6h).
Hi, thanks for your comment. We’ve only ever recommended using the NGK CMR6H with the MS 462 C-M. We use this same spark plug on many other machines too as it’s proven to be reliable and long-lasting. No STIHL machines are currently recommended with the NGK CMR5H, so we would recommend taking the chainsaw to a STIHL Approved Dealer if you are having reoccurring problems with the spark plug. Thanks, STIHL GB