Briggs & Stratton 491657S Oil Pressure Switch

The Briggs & Stratton 491657S oil pressure switch monitors engine lubrication pressure and activates a warning light or shutdown circuit when pressure drops to 3-5 PSI. It is a normally closed switch designed for engines equipped with full pressure lubrication and oil filter. The switch features a corrosion-resistant alloy body with a gold-plated electrical connector for reliable signal transmission. It directly replaces superseded part number 491657 and fits a wide range of V-Twin and Opposed Twin II cylinder engine series used in portable generators, riding lawn mowers, and pressure washers. Physical dimensions are approximately 1.00 x 1.00 x 2.00 inches (25.4 x 25.4 x 50.8 mm) with a weight of 0.8 ounces (22.7 g). The switch utilizes a standard threaded mounting interface compatible with Briggs & Stratton engine blocks. This component is critical for preventing catastrophic engine failure due to oil starvation in outdoor power equipment applications.