Ignition coil issue - 1974 Evinrude 9.9

[Kurtbag16]

I am new to this forum and self-taught/new with outboard repairs. Last year I replaced both ignition coils on my Evinrude when I found that one cylinder wasn't firing (spark plugs were new and one was consistently not getting spark). After I replaced the coils (with BRP coils), both cylinders were firing and the motor worked great for about 2 months. Then the same cylinder seemed to quit (while running, I got shocked after touching the boot of the non-firing spark plug). I took the multi-meter to the motor this spring and found that the spark-plug leads were good, but both coils had output resistance that was below what I found posted for spec (supposed to be 200-400ohms but found one to be 12 ohms and the other, bad coil, to be 6 ohms). The resistance on the primaries for the coils seemed to be good (1.1 ohms each). I couldn't figure out how to test the trigger or stator on my model of Evinrude, but I found that when I switched the connections from the magneto to the coils, the same coil was consistently bad, which I believe means that the problem is isolated to the coil. And I should specify, the low coil resistances were measured when the coils were off the motor.

My questions are:
1) why would my new coil resistances be below spec?
2) why is one coil half the resistance of the other?
3) what would cause a new coil to die within a few months?

 

[Crosbyman]

suggestion:

I would remove the coils and test primary and secondaries if the secondaries test OK at 200-400 ohms and you then get 6-12 ohms mounted....... the coil secondaries may be shorted internally to mounting bolts or punched or have burned the coil body which ends up touching the engine frame

 

[Kurtbag16]

Thanks for the reply! I should have specified, that the coils tested 12 and 6 when off the motor.

 

[flyingscott]

I would be looking at your points and condensers.

 

[jimmbo]

Then the same cylinder seemed to quit (while running, I got shocked after touching the boot of the non-firing spark plug).

If you got a shock, it appears that the coil is functioning, and perhaps there is a Problem with the Plug(cracked Insulator, carbon tracks on insulator)

 

[racerone]

Replace the sparkplug boots.

 

[saltchuckmatt]

When checking for spark and doing compression checks your coils need to be grounded otherwise you are putting extreme pressure on them.

I'm also assuming you have checked all grounds.

 

[Kurtbag16]

Hello all, thank you for your replies. I ended up getting one of my coils replaced on warranty (due to its failure). After getting both coils back on, I was seeing good spark when I spun the flywheel with the plugs out. However, when I started the motor up I found I was getting shocked when I touched the spark plug boots. This was also happening when the coil went bad last year. The spark plug leads and boots are both new, so I'm not sure where the issue might be. The coils are grounded and the ignition system appears to be properly grounded as well. I have included pictures in case anyone can see something that I am missing. I am also looking for guidance on checking the trigger and stator using a multi-meter. Non of the instructional videos I have found for 9.9's seem to have the type of wiring that mine has. I am also unable to remove the flywheel without sending the motor to a shop, which I am trying to avoid unless I can't figure this out.

 

[909]

Buy a harmonic balancer puller kit at your local parts outlet,.

 

[F_R]

There is a simple solution to the shock problem. Just don't touch the wires Most any motor will shock you if you touch the HT leads. I suppose there is a scientific explanation for it but I won't go there. Many instruments such as timing lights are "connected" to the wire by simply clamping to the outside.