Milwaukee (Oct. 12, 2021) — Briggs & Stratton announced that the Vanguard 400 single-cylinder engine, which has been converted to run on propane, has been certified by the Environmental Protection Agency (EPA) as compliant with the Clean Air Act emission standards. This is the first and only engine in its size class with a manufacturer's warranty to be converted to propane fuel and receive EPA certification, with California Air Resources Board (CARB) certification on the horizon in 2022.

When converted to propane, a less carbon-dense fuel source, the Vanguard 400 engine with a catalyst muffler provides a significant reduction in carbon emissions.

"This is the only engine in this size range that is EPA certified on propane. The engine is also equipped with a catalyst muffler rather than a standard muffler," says Chris Davison, senior marketing manager of commercial power at Briggs & Stratton. "Using a catalyst muffler and engine tuning, we are able to reduce carbon monoxide emissions by 80% to 95% and allow the engine to pass engine standards for hydrocarbons and oxides of nitrogen oxide standards. This level of emission reduction would be difficult with a carbureted gasoline engine."


The newly EPA-certified engine is on the market today with early customers testing the engine for their specific applications. While many commercial engines that are currently on the market can be successfully converted to propane, this does not mean they automatically meet the EPA certification and safety requirements. Vanguard engines feature safety devices on every propane conversion kit. These features include special lock-offs that block the fuel when the engine is idle, an engine data analyzer that records emissions levels, and CO monitors that record carbon monoxide levels.

"These are the cleanest, safest commercial engines on the market today," says Jim Coker, director of propane applications at Propane Power Systems. "After we retrofit the engines to propane, we take the important step of running and testing their emissions levels before we send them out the door. This extra step in quality control ensures the engine is running at the levels it needs to, and that it will provide optimal performance for the end-customer."