What is the right spark plug and gap for my engine?

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Checking and changing spark plugs is an essential step in routine engine maintenance and when troubleshooting problems with your outdoor power equipment.

Before doing any engine repair or maintenance, check your manual for recommendations on specific parts numbers and safety precautions.

Find Your Spark Plug Type & Gap

There are different types of spark plugs so be sure to use the correct one before replacing. You can see the different types shown to the left.

Once you have identified the correct spark plug, purchase your genuine Briggs & Stratton replacement spark plug here.

 Be sure to use the right spark plug. Although several different spark plugs may screw into the engine, using the incorrect one will result in performance problems and possible internal engine damage.

Where is the spark plug located on 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

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.

Replacement Part Type Replacement Spark Plug Part Number Spark Plug Gap
Standard Plug 491055S (RC12YC - Resistor) .030"
Platinum Extended Life* 496018S (RC14YC - Resistor - Hot) .030"
Gold Terminal (EMS)** 691043 (QC12YC) .030"
Resistor (EMS)*** 792015 (XC92YC) .030"

*Used in cold climate for better cold starts and extended life - less need to change
**Used on emergency medical equipment
***Used on emergency medical equipment or regular equipment

Horizontal Engines Spark Plug Location

Small Block V-Twin

Big Block V-Twin


Vertical Engines Spark Plug Location

Commercial Series

Small Block V-Twin

810CC V-Twin

Big Block V-Twin