It has 3 coils , one over each of 3 sparkplugs, then it has a plug wire from the side of these coils going to another cylinder,so each coil fires 2 cylinders just like a lot of cars.. the interesting thing is that the spark plugs that have the coil sitting on top of them wore from the center electode and rounded it off and away. The plugs that had the wire going to them wore from the top electrode. This was consistent on all of them.