NGK Spark Plug CMR6H 3365

Product Information

This spark plug has a resistor that is produced with a glass and carbon mixture, which is fired to ensure superior performance and durability. It has corrugated ribs that prevent flashover and cold rolled threads to inhibit damage to the cylinder head. A misfire occurs when the spark travels the path of least resistance instead of jumping across the gap. Misfires can be caused by the following: A hotter heat range spark plug has an insulator design with a longer heat flow path to the metal shell of the plug. As a result, more heat stays in the ceramic firing end and less is dissipated to the engine. A colder heat range spark plug has an insulator design with a shorter heat flow path to the metal shell of the plug. As a result, less heat stays in the ceramic firing end and more is dissipated to the engine. For a spark plug to function properly, it must have a tip temperature high enough to burn off carbon deposits (self-cleaning) and avoid fouling, while remaining low enough to avoid overheating the ceramic firing end and pre-ignition. Fouling can occur more easily if the air-fuel mixture is not adjusted to compensate for the altitude. Higher altitude = less air = less fuel. SKU: PLCMR6HX Category: Spark Plugs Tags: 0000-400-7009, 0000-400-7011, 100, 101, 110, 130, 131, 168652-4, 31916-Z0H-003, 3365, 345FR, 439, 526XP, 531008615, 545, 545FX, 545FXT, 545RX, 545RXT, 550XP, 550XPG, 555, 556, 560XP, 560XPG, 562XP, 562XPG, 574519601, 6778, 90119, A425000040, BG56, BG66, BG86, Bosh, BR200, BR500, BR550, BR600, BR700, BT131, Champion, CMR6H, CMR6H-SLDCAP, CS2252, CS2253, CS2258, CS2260, CS2260WH, FC100, FC110, FC56, FC70, FC90, FC95, FR130, FR410, FR460, FR480, FS, FS100, FS110, FS111, FS130, FS131, FS240, FS25, FS260, FS310, FS311, FS360, FS40, fs410, FS460, FS460 C-EM, FS50, FS56, FS65, FS70, FS87, FS89, FS90, FS91, FS94, GX25, HL100, HL90, HL91, HL94, HL95, Honda, HQT-3, HS46, HS46 C-E, HS56, HS56 C-E, HS81, HS82, HS86, HS87, HT100, HT101, HT102, HT103, HT130, HT131, HT132, HT133, HT56, Husqvarna, Jonsered, KM100, KM110, KM111, KM130, KM131, KM56, KM90, KM94, Makita, MS 201 T, MS 201 TC, MS150, MS150 C-E, MS170, MS171, MS180, MS181, MS181 C, MS192 C-E, MS193C, MS193T, MS201, MS211, MS211 C, MS231, MS241, MS241 C-M, MS251, MS362, NGK, Plug, RZ7C, SH200, SH56, SH86, Shindaiwa, Spark, SR200, Stihl, T2600, T435, T540XP, USR4AC Related products

As the air temperature or humidity increases, the air density decreases, requiring a leaner air-fuel mixture. If the air-fuel mixture is too rich, decreased performance and/or carbon fouling can result. 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. 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.https://www.ngkntk.com/newsroom/feature/emea/2020-1/counterfeit-spark-plugs-the-ignition-villains-that-could-ruin-your-engine/ One of the most misunderstood aspects of spark plugs – is the heat range. One misconception is that the heat range is related to the spark temperature or intensity. Another common misconception is that the spark plug is designed as a heat sink to “remove” heat from the combustion chamber. These ideas are both false. The spark plug is heated during combustion and must dissipate that heat to the cylinder head at a certain rate to avoid overheating the ceramic firing end. The spark plug heat range only indicates the rate that the spark plug dissipates its firing end heat to the engine. The heat range must be carefully selected for proper spark plug thermal performance. If the heat range is not optimal, then serious trouble can be the result. The optimal firing end temperature is approximately 500°C (932°F) to 800°C (1472°F). The two most common causes of spark plug problems are carbon fouling (< 450°C) and overheating (> 800°C). When the spark plug firing end (tip) temperature exceeds 800°C, pre-ignition originating from the overheated insulator ceramic can occur.

Carbon fouling occurs when the spark plug firing end does not reach the self-cleaning temperature of approximately 450°C (842°F). Carbon deposits will begin to burn off from the insulator nose when the self-cleaning temperature is reached. When the heat range is too cold for the engine speed, the firing end temperature will stay below 450°C and carbon deposits will accumulate on the insulator nose. This is called carbon fouling. When enough carbon accumulates, the spark will travel the path of least resistance over the insulator nose to the metal shell instead of jumping across the gap. This usually results in a misfire and further fouling. The spark plug heat range has no relationship to the electrical energy transferred through the spark plug. The heat range of a spark plug is the range in which the plug works well thermally. The heat rating of each NGK spark plug is indicated by a number; lower numbers indicate a hotter type, higher numbers indicate a colder type. NGK is the brand leader in the UK spark plug market and are the world's biggest supplier to many major car manufacturers. Each and every one of their products are designed to meet the most rigorous standards and are the professionals' choice because of their quality and technical excellence. Their plugs can be found in use by teams in F1, WRC and MotoGP. Put simply, NGK genuine spark plugs are the workhorse at the heart of smooth-running engines around the world. As a general guideline, among identical spark plug types, the difference in tip temperature from one heat range to the next is approximately 70°C to 100°C.

The primary function of the spark plug is to ignite the air-fuel mixture within the combustion chamber under any operating condition. Mismatched ignition system components (plug resistance/wire resistance, ignition coils/igniter modules, etc.) This spark plug features a triple gasket sealing process that eliminates fuel leakage. It also comprises a solid copper core that gives superior heat dissipation and conductivity.

Spark plugs have been around as long as internal combustion engines have and are often a misunderstood component. This basic guide is designed to assist the technician, hobbyist or race technician in understanding, using and troubleshooting spark plugs. Image are for illustration purposes only and may not reflect dealer inventory or unit specifications.There are many external influences that can affect the operating temperature of a spark plug. The following is a brief list to consider in avoiding reduced performance and/or expensive engine damage. Engine Speed and Load The spark plug firing end temperature must be kept low enough to prevent pre-ignition, but high enough to prevent fouling. This is called “thermal performance,” and is determined by the heat range selected. It is most often caused by the wrong (too hot) heat range spark plug, and/or over-advanced ignition timing. An improperly installed (insufficient torque) spark plug can also result in pre-ignition due to inadequate heat transfer.

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. Advancing ignition timing by 10° will cause the spark plug tip temperature to increase by approximately 70° to 100°C. Air (atmospheric) pressure and cylinder pressure decrease as altitude increases. As a result, spark plug tip temperature will also decrease.

Excessively rich air-fuel mixtures can cause the plug tip temperatures to decrease and carbon deposits to accumulate, possibly causing fouling and misfires. If the engine is to be operated at high RPM, under a heavy load or at high temperatures for long periods, a colder heat range may be needed. Illustrations may differ slightly from original product and are not assembled, but in boxes for shipment.