NGK CMR6H Spark Plugs 3365 — Pack of 10 for Chainsaws & Outdoor Power Tools, Copper Core 10mm

These NGK 3365 / CMR6H plugs are manufactured to original-equipment tolerances and engineered for everyday outdoor power equipment use. They pair a solid copper core with nickel electrodes and a 5-rib alumina silicate insulator to reduce flashover, improve heat transfer and simplify installation and removal. Each pack contains ten plugs—convenient for professional crews or seasonal maintenance of multiple machines.

Which tools and models work with the NGK CMR6H (3365)?

The CMR6H is compatible with many popular chainsaw and small-engine models from major brands. It fits a range of STIHL chainsaws and accessory equipment, certain Husqvarna and RedMax engines, plus common trimmers, blowers and hedge trimmers from other manufacturers. Always cross-check thread size, reach and heat range before purchase.

• STIHL chainsaws: MS150TC, MS171, MS181, MS181C, MS201, MS201C, MS201T, MS211, MS211C, MS251, MS251C
• REDMAX: GZ4000; Husqvarna: 545, 555, 526XP
• Outdoor equipment: Jonsered brushcutters/trimmers, Poulan Pro hedge trimmers, Shindaiwa trimmers/brushcutters, STIHL blowers and sprayers

What are the key technical specs and design benefits of these plugs?

NGK built the CMR6H to combine dependable ignition with simple serviceability. The copper core improves conductivity and expands usable heat range, while nickel electrodes and a nickel-alloy center offer robust wear resistance. Cold-rolled threads and NGK’s triple-gasket sealing minimize cylinder head damage and gas leakage during operation.

• Thread diameter: 10 mm; reach: 7 mm; hex/wrench size: 5/8 in
• Gap: 0.028 in; resistor value approximately 10K ohm; single ground electrode
• Materials: 98% pure copper core, nickel center and ground electrodes, alumina silicate insulator with 5-rib design

How do these plugs affect maintenance and performance on small engines?

Using OE-standard NGK plugs reduces misfires and keeps ignition consistent across varying fuel and load conditions. The solid copper core helps dissipate heat efficiently, lowering the risk of fouling in typical outdoor-use environments. Cold-rolled threads and treated porcelain simplify swapping plugs during routine service.

• Reliable starts and steady idle for handheld equipment
• Improved heat dissipation to widen safe operating range
• Durable construction that resists thread damage and gas leakage

What should I check before installing the NGK 3365/CMR6H plugs?

Confirm the plug’s thread diameter, reach and heat range match your engine’s specifications and owner’s manual recommendations. Inspect the gap and adjust if necessary to your equipment’s required setting. Use proper torque with a 5/8-inch wrench and ensure the triple-gasket seat is clean for a tight seal.

• Verify model compatibility and thread/reach (10 mm thread, 7 mm reach)
• Check and set the 0.028 in gap as required by the engine
• Hand-start threads then torque to manufacturer spec to avoid damage

Who is this for? NGK CMR6H (3365) spark plugs are aimed at professional landscapers, equipment rental shops and homeowners who maintain multiple chainsaws or handheld machines. If you need OE-quality ignition parts that are easy to install, offer dependable starts and match common small-engine models from STIHL, Husqvarna, RedMax and others, this ten-pack supplies spare plugs for routine service and seasonal tune-ups.