I have a 1977 johnson 15 it was running fine all spring, i took it out the other day and i have no spark in the top plug. i have tested the coils with an ohms meter and they are testing good. i know the stator and trigger are working because i have spark on the bottom plug. how would i go about trying to fix this without replacing everything, being the parts are expensive i dont want to buy more than what i need. also, the coils are wired into the same harness, if i had to buy the coils will they come as a pair with the correct end for the aplication or do i have to rewire them into the harness, any help from someone would be greatly appreaciated. thank you