This thread deals with lack of spark or ignition issues with the P216, P218 and P220 engines used in the late 80s and all 90s tractors originally equipped with the Onan. this would be your 3,4,500 series tractors that typically look like the one below with the Onan twin engine......     Parts of the manuals you will need to diagnose the issue........       testing of these components is also in the demystification guide as well.....             typical engine wirin