Re: Need Help. 1974 85HP. Ignition Problem.
Those type coils are known to crack but they may be fine. If you don't see sparks flying out of them, check their continuity and if okay, coat them with liquid neoprene and use them.
(Magneto Capacitance Discharge Coils - Continuity Test))
(J. Reeves)
Check the continuity of the ignition coils. Remove the primary orange wire from whatever it's connected to. It may be connected to a powerpack screw type terminal, a rubber plug connector, or it may simply plug onto a small boss terminal of the coil itself.
Connect the black lead of a ohm meter to the spark plug boot terminal, then with the red ohm meter lead, touch the ground of the coil or the powerhead itself if the coil is still installed.
Then touch (still with the red lead) the orange wire if it's attached to the coil, or if it's not attached, touch the primary stud of the coil. You should get a reading on both touches (contacts). If not, check the spring terminal inside the rubber boots of the spark plug wire. Poor or no continuity of a coil is one reason for s/plug fouling.
Spark test: Remove spark plugs and rig up a spark tester so that you can st a 7/16" gap. The 7/16" gap is important. No tester... build this one.
(Spark Tester - Home Made)
(J. Reeves)
A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.
Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:
..........X1..........X2
.................X..(grd)
..........X3..........X4
Now, disconncet the large RED electrical connector at the engine. Crank the engine by using a small jumper from the battery cable terminal of the starter solenoid to the small 3/8" nut of the solenoid that energizes the solenoid. If you have spark with that RED plug disconnected but no spark with it connected, replace the ignition switch.
If still no spark, look under the flywheel at the stator. If that stator (round green ring) is cracked and has a sticky looking substance dripping out of it down on the powerhead..... that would cause a AC voltage drop to the powerpack, in which case, replace the stator. If the stator looks okay, remove the brown and the brown/yellow wire from the powerpack and check the ohm reading (in your manual or someone else can tell you what that is).
If all of this checks out okay, the usual problem is that the powerpack has failed.
