Rather than horsepower, Briggs & Stratton uses gross torque ratings for engines powering walk-behind lawnmowers, pressure washers, tillers, and other specific applications.
While horsepower has been traditionally been used for these applications, torque ratings are not new for engines. Gross Torque is the immediate twisting force required to turn a blade or pump at a given moment. So, torque is the way to measure the rotational force a machine can produce - i.e. exactly what a walk behind mower does as it cuts grass or a pressure washer as it pumps water - and more accurately describes the capability or job capacity of an engine for these applications.
However, horsepower is maintained as a measure of power for our larger engines. These models are often used in applications, such as a riding lawnmower, that may require engine power to be distributed to multiple areas of the equipment such as transmission, wheels, hydraulics, etc.). Horsepower is a more meaningful measure of an engine's power in these types of applications.
If you are uncertain as to the gross torque or horsepower rating of your engine, we invite you to Ask a Question or call our Briggs & Stratton Answer Center at (800) 444-7774 (8:00 am - 5:00 pm CST) with your engine Model, Type, and Code Numbers, and we will be happy to assist you.
For related information, please download our Torque Questions & Answers PDF, visit our New Engine Series Labeling FAQ and/or view our "Get to Know Torque" video below.
Engine Power Rating Information
The gross power rating for individual gas engine models is labeled in accordance with SAE (Society of Automotive Engineers) code J1940 (Small Engine Power & Torque Rating Procedure), and rating performance has been obtained and corrected in accordance with SAE J1995 (Revision 2002-05). Torque values are derived at 3060 RPM; horsepower values are derived at 3600 RPM. Actual gross engine power will be lower and is affected by, among other things, ambient operating conditions and engine-to-engine variability. Given both the wide array of products on which engines are placed and the variety of environmental issues applicable to operating the equipment, the gas engine will not develop the rated gross power when used in a given piece of power equipment (actual "on-site" or net horsepower). This difference is due to a variety of factors including, but not limited to, accessories (air cleaner, exhaust, charging, cooling, carburetor, fuel pump, etc.), application limitations, ambient operating conditions (temperature, humidity, altitude), and engine-to-engine variability. Due to manufacturing and capacity limitations, Briggs & Stratton may substitute an engine of higher rated power for this Series engine.