Reply To: EVINRUDE trigger coil

[Don]

Rick Robbins wrote:

Followed the service manual troubleshooting directions for no spark on any cylinder. Everything was as expected until I came to the sensor coil. At that point I had .06 v instead of the required .3 v between pin D and pins A,B and C. Then the resistance checks were: D to E=446 ohms, D to A,B,C was measuring open on any scale. Since I was not getting the results the shop manual indicated, I figured the sensor coil was defunct. Couldn’t see continuing when I had results that were not what the manual called for. I’m open to suggestions that indicate I’m missing something. Not looking to spend money chasing an incorrect diagnosis.

Admittedly don’t have a manual close by, but remember the long/sensitive process. This part is so sensitive that I’m pretty sure the manual mentions different resistance readings that might be found on a few different brand ohm meters…I believe the term “impedence” was tossed around also. Were you using a peak reading voltmeter when checking the voltage output? If so, was it set to the proper scale? I won’t be home for a week or so, perhaps Dan can review the sensor troubleshooting procedures with you. In any event, the sensor works in two modes, quikstart and run. There are several tests to check output/resistance in both modes.
In any event, the sensor would not be my “first bet” in a no spark situation, unless you found damaged/burned/melted leads. Did you do the key switch elimination test? Did you check the pack and coil ground connections with an ohm meter on the low scale? Those amphenol connections can be troublesome also, did you check each black plug to make sure none of the pins/sockets were bent or partially pushed out? Please don’t be offended if I ask if the emergency stop lanyard is properly attached to the control or switch on the dash….Happens to the best of us.
Have you checked the powerpack charge coil resistance and output? If so, did you use a peak reading voltmeter? There is a “power coil” that provides power for the quikstart/SLOW systems also, but I’m pretty sure the engine will still spark even if the power coil is bad.
Please know that I am not trying to question your troubleshooting methods/results, but the sensors would not be my first guess. I would surely want to eliminate all other simpler causes before replacing the sensor assy. Again, this part is very expensive, and most dealers would not offer a refund once it has been installed.
When was the last time this engine had spark, what has changed since then? Is the battery fully charged? Low cranking speed can cause no spark due to low charge coil/sensor output.
Don