1989 115 HP Mariner only runs on 2 cyls. Now only on one of the 4. It would run on 2 most times I took it out then pick up the other 2 in 2-5 minutes of running wide open. Now wil only run on 1 cyl. I'm 99.9% sure it's spark but don't really want to just start replacing stuff like CDI , stator...
