STIHL ZK C 10 Spark Plug - Genuine OEM Replacement for STIHL 2-Stroke Engines - 0000 400 7025

The STIHL ZK C 10 Spark Plug (OEM part number 0000 400 7025) is a genuine replacement ignition component for a wide range of STIHL 2-stroke petrol-powered handheld tools used across UK arboriculture, forestry, landscaping and grounds maintenance. With an M10 x 1.0mm thread, nickel alloy electrodes and a corrosion-resistant plated steel shell, the ZK C 10 is engineered to STIHL's heat range and reach specification for the listed engine types, delivering consistent spark generation for reliable cold and hot starting, stable idling and clean acceleration across the rev range. Sold individually as a direct replacement for a worn, fouled or damaged original plug. Available from Gustharts, an authorised STIHL dealer with UK stock ready to ship.

The ZK C 10 is compatible with STIHL 2-MIX and M-Tronic engines, and covers a broad platform range including brushcutters, clearing saws, chainsaws, blowers, hedge trimmers and KombiMotor powerheads. Always set the electrode gap to your machine's service specification before installing — refer to the Technical Data section of your operator's manual for the correct gap for your specific model. The equivalent Bosch alternative is the Bosch USR4AC. Also available in a pack of 40 under part number 0000 400 7026.

Key Features

• Genuine STIHL ZK C 10 spark plug — manufactured to STIHL OEM specification for heat range, reach and electrical performance matched to listed engines
• M10 x 1.0mm thread — smaller diameter than standard 14mm STIHL plugs; ensure you are ordering the correct specification for your model before purchasing
• OEM part number 0000 400 7025 — also formatted as 00004007025; pack of 40 available separately under 0000 400 7026
• Sold individually (each) — single plug per order
• Fixed union nut — prevents an unintended spark gap that could impair ignition performance or create a fuel vapour ignition risk
• Interference suppression resistance — tuned to STIHL ignition systems for optimal spark timing and protection of the ignition module against premature failure
• Coated sealing ring — improves contact and corrosion resistance in wet and demanding outdoor working conditions
• Nickel alloy electrodes — durable construction suited to regular service intervals in professional and domestic use
• High-alumina ceramic insulator — provides electrical strength and thermal stability across the operating temperature range
• Compatible with STIHL 2-MIX and M-Tronic engines — suitable for electronically managed and mechanically carburetted engine variants
• Set gap to machine specification before fitting — refer to your model's operator manual for the correct electrode gap

Technical Specification

Important Use Guidance

Confirm your model requires the ZK C 10 (M10 thread) before ordering. This plug uses a 10mm thread diameter. Many STIHL tools use 14mm thread spark plugs (such as the NGK BPMR7A or CMR6H). These are not interchangeable — fitting the wrong thread size will cause engine damage. Always check the Technical Data section of your operator's manual or the Fits Models list below before purchasing.

Set the electrode gap before fitting. Always verify and adjust the electrode gap to your machine's stated service specification using a feeler gauge before installation. The correct gap varies by model and is specified in your operator's manual.

Replace at the correct service interval. STIHL recommends inspecting the spark plug regularly and replacing it at the service interval stated in your machine's manual — typically every 100 operating hours or annually for most professional equipment, whichever comes first.

Why Choose Genuine STIHL Spark Plugs Over Aftermarket Alternatives?

STIHL spark plugs are engineered with specific features that aftermarket alternatives do not reliably replicate. The fixed union nut prevents accidental spark gaps that can impair ignition or — in worst-case scenarios — ignite fuel vapour outside the combustion chamber. The interference suppression resistance is tuned specifically to STIHL's ignition module characteristics, reducing the risk of premature ignition module failure that can occur when a plug with incorrect suppression resistance is fitted. The sealing ring coating supports a gas-tight seat and resists corrosion in the wet, contaminated conditions typical of outdoor professional use.

For a low-cost consumable where the failure consequences include hard starting, misfiring, ignition module damage and unplanned downtime on a professional tool, the difference in cost between genuine and aftermarket is rarely worth the risk. For workshops and fleet operators managing multiple STIHL tools, the pack of 40 (0000 400 7026) offers better per-plug value for routine scheduled servicing.

Fits Models

• STIHL BG 56
• STIHL BG 56 C-E
• STIHL BG 66-D
• STIHL BG 86 C-E
• STIHL BR 500
• STIHL FR 460 TC-EM
• STIHL FS 38 2-MIX
• STIHL FS 50 (4144)
• STIHL FS 50 C-E
• STIHL FS 55 2-MIX
• STIHL FS 55 R 2-MIX
• STIHL FS 56 (4144)
• STIHL FS 56 C-E
• STIHL FS 56 RC-E
• STIHL FS 70 C-E
• STIHL FS 131 R
• STIHL FS 240
• STIHL FS 240 C-E
• STIHL FS 360 C-EM (4147)
• STIHL FS 361.0 C-EM
• STIHL FS 411.0 C-EM
• STIHL FS 460
• STIHL FS 461 C-EM
• STIHL FS 461.0 C-EM L
• STIHL HS 87 R
• STIHL HS 87 T
• STIHL KM 131 R
• STIHL MM 56
• STIHL MS 151 C-E
• STIHL MS 151 TC-E
• STIHL MS 162
• STIHL MS 172
• STIHL MS 201 TC-M
• STIHL MS 212 C-BE
• STIHL MS 231 C-BE
• STIHL MS 241 C-M VW
• STIHL MS 362 C-M
• STIHL MS 400 C-M
• STIHL MS 400.1 C-M VW Arctic
• STIHL MS 500i-W
• STIHL SH 86

Also Known As

The STIHL ZK C 10 is also referred to as a small engine spark plug, petrol engine spark plug, ignition plug and, colloquially, a STIHL plug 0000 400 7025. The designation "ZK C 10" identifies this as a STIHL 10mm thread plug — distinct from the larger 14mm thread plugs (such as BPMR7A and CMR6H) used in other STIHL tools. The Bosch equivalent designation is USR4AC. For correct ordering always use OEM part number 0000 400 7025 for the single plug or 0000 400 7026 for the pack of 40.

Often Replaced Alongside

Spark plugs are typically replaced as part of routine scheduled servicing. Common items to inspect and replace at the same service interval:

• Air filter for compatible model — inspect and replace at standard service intervals alongside the plug
• Fuel pick-up filter — replace at scheduled service intervals on most STIHL 2-stroke tools
• Sharpening and maintenance tools — keep cutting equipment serviced alongside engine components

Explore More

• STIHL Spare Parts
• STIHL Parts Finder
• STIHL Machinery

FAQs

What is the difference between ZK C 10 and other STIHL spark plugs?

The ZK C 10 uses an M10 x 1.0mm thread — smaller than the 14mm thread used in NGK BPMR7A and CMR6H plugs. These are not interchangeable. Always confirm your model requires the ZK C 10 before ordering by checking your operator's manual or the Fits Models list.

What is the part number for the STIHL ZK C 10 spark plug?

The OEM part number is 0000 400 7025, also formatted as 00004007025. A pack of 40 is available under part number 0000 400 7026.

What is the electrode gap for the STIHL ZK C 10?

The electrode gap varies by model. Always refer to the Technical Data section of your machine's operator manual for the correct gap specification and set it with a feeler gauge before fitting.

Is there a Bosch equivalent for the STIHL ZK C 10?

Yes. STIHL UK confirms the Bosch USR4AC as the equivalent alternative. The STIHL ZK C 10 OEM plug is the recommended first choice for optimal performance and ignition module protection.

How often should I replace the spark plug on a STIHL tool?

STIHL recommends inspecting the plug regularly and replacing at the service interval in your manual — typically every 100 operating hours or annually, whichever comes first. Replace immediately if you see fouling, cracking, electrode erosion or oil contamination.

Can I use the ZK C 10 in a STIHL 4-stroke engine?

No. The ZK C 10 is designed for STIHL 2-stroke petrol engines. Do not fit it to 4-stroke engines such as those in STIHL petrol lawn mowers or tillers, which require a different plug specification.

Is this plug compatible with STIHL M-Tronic engines?

Yes. The ZK C 10 is compatible with STIHL 2-MIX and M-Tronic engine variants as listed in the Fits Models section above.

UK Delivery

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