Things You'll Need:
- screw drivers
- a SAE ratchet and socket set
- Coil from a 1983 Evinrude 7.5 hp, similar coils can also be used.
- Black automotive silicone
- Electrical tape
- Container for draining gas
- 2 X 90 degree spark plug boots
- 8 inches of spark plug wire
- Fire extingguisher for safety.
- Peak reading multimeter
- Wire strippers
- male spade terminal I used blue insulator
- 1.5 inch bolt and matching nut,
- 2 washers and a lock washer.
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Step 1
Cowling off.......Remove cowling. Put in gear shift in neutral and remove prop. Drain gas out of tank and lines. Identify wire from CDI unit under flywheel.
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Step 2
Sheathed wire from CDI under fly wheelIdentify and narrow problem down to the coil. Do this by seeing if there is any voltage coming from the wire that comes from the CDI unit using a peak holding multimeter set to 300 Volts.Shut off fuel valve.Yank starter a few times after removing spark plug to get reading and to make sure engine will not start. Make sure ignition wire is in good condition. If no spark at the plug suspect coil.
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Step 3
EMPTY on board gas tank from block, disconnect fuel line from tank drain any remaining gas. Have fire extinguisher handy just in case. Safety first. Do this in a well ventilated space away from flammable stuff.
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Step 4
Disconnect wire from CDI to coil at the coil it has a spade type terminal. Disconnect spark plug wire from spark plug. Remove coil by undoing 2 screws that hold the coil to the gas tank/ cooling shroud.
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Step 5
broken original coilInspect old coil for cracks, a good indication it has broken. The one in the picture is broken see cracks in epoxy type insulation.
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Step 6
Now prepare new coil for transplant. Attach a male spade terminal to coil input wire. Attach to wire from CDI. Coat with black silicone so no metal is showing and it is water proof. Let cure. Then wrap in electrical tape. Attach ground wire from new coil to a good ground anywhere on engine using the old screw that was used to attach the old coil. I attached ground to one of the old holes the old coil was attached to, sanding off some paint to get a good ground.
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Step 7
Attach new coil to one of the holes hanging off the gas tank/ cooling shroud. I used the bolt with the washers and a lock washer on the nut side through bolt hole in the new coil. Spark plug wire terminal facing towards head and out. Then bend the attachment tab in so cowling fits with no problem.
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Step 8
Assemble the spark plug wire with the 90 degree boots on both ends with the internal connectors crimped and properly positioned. You'll have to put them on the wire first then shove then through the boot, this may take some patience. Some dielectric grease may help. Sometimes you can find the right length of spark plug wire already assembled from an auto parts store.
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Step 9
Attach wire and boot assembly...one end to coil...one end to spark plug. If you did everything right and it was the coil that was the problem. You will now have spark at the park plug.
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Step 10
Make all wires nice and neat, and keep from rubbing and moving parts. Reattach fuel line and cinch on fuel nipple with appropriate clamp. Reattach gas tank and shroud. Once that is done you can yank on the rope starter and check for spark with spark plug removed and grounded to block and see if it sparks. BECAREFUL you can get a very nasty electrical shock. If you have a pace maker don't try this.
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Step 11
If all is well reinstall cowling, fill with the proper oil/fuel ratio and go and test it.
