Alright guys, i'm about at my wit's end with this motor. I have a 1986 Mariner 60 hp 3 cylinder. For some reason I'm not firing on cylinder #3. The motor will idle and run up to about 2000 rpm, and then will die with continued throttle. If I throttle up slowly it will climb to 3000 rpm and no higher, no matter how much throttle I give it. I went over the fuel system top to bottom, rebuilt the carbs and fuel pump (both were needed anyway) and it's solid. All 3 cylinders have good compression. After replacing the plugs and running the motor for a bit I checked the plugs again. 1 and 2 had signs of firing, but #3 looked like it just came out of the box. I used a spark tester and comfirmed that #3 has spark but seemed very weak compared to the other cylinders. While idling I pulled each of the spark plug wires. When #1 was pulled it killed the engine, #2 dropped rpm severely, but #3 only slightly dropped the rpm. I did a coil substitution and the problem stayed on the #3 cylinder no matter which coil was firing it. I used and ohm meter and got good resistance readings on the trigger and coils, but could not get a reading on the low side of the stator and the high side measured out of spec. I'm thinking it could be either the switchbox or the stator, or both for that matter, but I'm unsure how to proceed, and I don't want to throw money at both parts if I only need one. The fact that there's only 1 cylinder without spark and that the problem did not change after substituting coils leads me to the switchbox, but I'm also concerned about the the stator measurements. Then again i was under the impression that a stator would lead to problems on multiple cylinders, and I'm not sure that I can trust the multimeter on all the readings. I've read other threads where guys got bad readings and the stator was fine. If I pull the switchbox will a mercury dealer be able to test it? Am I on the right track?
