First trip to the Mercury forum. 1987 Mercury 80 hp seems to be running on only one cylinder. Compression is at an even 100 on all three cylinders. Spark gap test jumps 7/16 hot. Carbs rebuilt. Top cylinder firing and other 2 no noticeable difference when removing the plug wires. When top plug wire Is removed it will sputter a bit and shut down. Moved coils, wires and plugs to different cylinders with no difference. Sprayed gas mixture into carbs and no change in the middle and bottom cylinder. I’m stumped. Any ideas? Thanks in advance.
