Briggs & Stratton 5 HP Quantum Vertical Engine. Quantum engines are designed with performance and dependability in mind. Known for easy starting and power, Quantum engines also have larger muffler for quiet operation. Prime'N Pull easy starting system delivers the right amount of fuel to the carburetor for consistent one-pull starts. Large rewind starter reduces pulling effort for easy starting. Magnetron Electronic Ignition System ensures dependable starts with no maintenance required. Composite camshaft & aluminized lo-tone muffler results in a corrosion-resistant, quiet running engine. Mechanical governor controls the throttle to deliver more power for heavy mowing conditions. Mechanical compression release provides smooth, easy starts and ensures engine reaches maximum power instantly. Lubrication system is gear-driven to continuously supply oil to all internal engine parts for extra protection and long life. U.S.A.