Identifying the Correct Spark Plug and Gap
What is the correct spark plug and gap for my engine?
Due to the variety of engine and equipment configurations, your best source for spark plug information is your engine or equipment Operator's Manual. However, the following general guidelines will get you pointed in the right direction.
This guide provides the common spark plug part numbers used in our L-Head and Overhead Valve engines. For information regarding the service/replacement of spark plugs, please visit our Servicing the spark plug FAQ. Please be aware that the size/shape of the spark plug varies depending on engine design.
Briggs & Stratton L-Head Engines
(also referred to as Flat Head or Side Valve Engines)
Use any of the following spark plugs gapped at .030" in our L-Head engines:
B&S 796112S, 802592S or 5095 - Standard Resistor Spark plug
B&S 697451 - Electromagnetic Suppression (EMS) Spark Plug
B&S 796560 or 5062 (5062D, 5062H) - Extended Life Series® L-Head Spark Plug (Platinum). Spark plug may have production number 499730 printed on porcelain.
(These spark plugs replace Champion CJ8, RCJ8, RJ19HX, J19LM, and RJ19LM).
B&S 591868 - Replaces Champion plug RJ19LMC (specifically gapped at .020"). Used in both older and current production Quantum engines. This spark plug is pre-set to .020" (.51mm) gap, which is the correct specification for Quantum engines manufactured after Code Date 110630xx.
Please be aware that the gap for this plug must be adjusted to .030" (.76 mm) gap for Quantum engines manufactured before Code Date 110701xx (for assistance in locating your engine's Date Code, please visit our Engine Identification FAQ).
B&S 799876 - Replaces Champion plug RJ2YLE. For use in Quantum Series 625, 675, and 725 engines built after Date Code 110701xx. The gap for this spark plug should be set to .020". This spark plug should not be used with Quantum Series 625, 675, and 725 engines built before Date Code 110701xx, or any other L-head engine family.
B&S 591040 - replaces the .020" gapped "Surefire" plug RJ2YXLE, which are often used in Craftsman Smooth Start (MRS) lawn mower applications.
Briggs & Stratton Overhead Valve (OHV) Engines*
Use the appropriate spark plug gapped at .030" in our Overhead Valve engines:
B&S 711252 - Resistor Spark plug∆ (Replaces Champion RC12YC)
B&S 491055S - Resistor Spark plug (Replaces Champion RC12YC)
B&S 691043 or 792015 - Electromagnetic Suppression (EMS) Spark plug (Replaces Champion QC12YC)
B&S 696202 or 5066 (5066D, 5066H) - Extended Life Series® OHV Spark Plug (Platinum). Spark plug may have production number 694385 printed on porcelain. (Replaces Champion RC12YC).
B&S 496018S or 5092 - Resistor Spark plug (hotter spark) (Replaces Champion RC14YC)
B&S 692051 - Resistor Spark plug
B&S 692720 - Electromagnetic Suppression (EMS) Spark plug
∆ Used on Vanguard models 050032 and 086400 only.
*Except Intek single-cylinder vertical shaft engines, as well as 550e, 550ex, 825, 850, and 875 Series vertical shaft engines. For these engines, use the spark plug's listed below (sparkplug gap - .020").
CAUTION! Be sure to use the right spark plug! Although several different spark plug's may screw into the engine, using the incorrect one will result in performance problems and possible internal engine damage.
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