Re: 1987 20 hp johnson no spark
Skip the fuse, not the problem. There will be a fuse only if you have an electric start engine and it will control the starting system only. This engine has few component. 1 charge col, 1 sensor coil, 1 power pack, 2 ignition coils and a kill circut. The fly whell could be included in the system but I have very seldom run into a fly wheel issue with this engine. First of all unhook the black wire with the yellow tracer from the power pack connector, this will eliminate the entire kill circut. ( make sure plug wires are unhooked from plugs.) I recomend leaving plugs in the head so if spark does return you dont have fuel coming out of the plug holes looking for an ignition source. Things can get really pretty when raw fuel finds spark! If there is still no spark it pans out like this. The charge coil under the fly wheel charges the ignition system for both cylinders, the sonsor coil under the flywheel tells the power pack witch cylinder to fire. So you have the possibliity of a faulty charge coil, faulty sensor coil and a faulty power pack. If you have checked the resistance on these coils and they are in range there is no test for the power pack except replacement. The power pack will be the cause the majority of the time. But there are always the strange failures.
