@Max Mustermann These engines are not illegal, they just have restrictions on how they can be used. You can't use them in some on-road vehicle, but they're fine for stationary applications. Though with how anal the EPA has been getting, this may no longer be the case in a few years, the EPA and several libtard tree hugger government agencies have been increasingly going after off-road and agricultural engines to make them more efficient and less polluting. This means expensive redesigns and expensive pollution control devices like DPF reactors for diesel engines and catalytic converters for gasoline engines. So far they've not retroactively applied such rules, except in California, which is a lost cause.