Please help!!
I have a 1984 Mercury 90hp Inline 6 outboard (serial #A176423) that's driving me crazy right in the middle of fishing season. I am not getting fire to #3 and #5 plugs. I replaced both #3 and #5 coils which seemed to remedy the problem until the next trip out. It seems both cylinders only get fire sporadically; all other cylinders will jump a ½” gap w/ a nice blue flame. It appears that #3 and #5 coils run to different switch boxes. Could it be that both switch boxes have gone bad or does it sound more like a stator problem? All wires and grounds appear to be good. I ran the entire electrical test / ohms test that I could find in the repair manual and all checks were good. Their was no test recommended for the switch boxes. My switch boxes are 332-7778-1a. If it is the switch boxes will a 332-7778a12 interchange?

I really appreciate any help offered very much!!

Thanks,
Curtis