Have you poured fuel that you’ve stored for a while in an engine and it won’t start? The fuel could be stale. Whether it’s in a can or a fuel tank, it can lose some of its effectiveness if it sits for long periods. Moisture and corrosion can set in and clog fuel systems, which can cause hard/no starting. This is particularly common in small engines that aren’t used often or just used seasonally. Additives that help keep fuel “fresh” can help avoid this problem.