Re: 78 Mercury no spark in #2 cyl
Pull all of your plug wires and measure resistance from the cap to ground, mine were about 1100 ohms each. Then remove the input wire to the terminal on the coil and measure that to ground, it will have little resistance. Measure each plug wire from cap to plug, the plug wires pop into the coil but they are tight. If you find a difference in comparing the test readings, you will have diagnosed a bad coil or a bad wire.
If you do have a bad plug wire, do not run it. The field created in the coil has to go somewhere, if it isn't connected to the spark plug, it will find it's way to ground thru the side of the coil. Coils do go bad, my #3 went due to a broken wire caused by a careless mechanic yanking on the wire to change plugs.
There are at least two different coils used on those motors, a cheaper one ($25) and a more expensive one ($65) ... guess which one mine used ...LOL, and they aren't interchangable. They changed the part number on the more expensive one so research will be in order.
its the dummy that yanked wire!!!!
