1986 120 Evinrude Spark Cuts in and Out

[djwock]

Hi,

This problem started intermittently. The Engine would rev up for about 1 second and then cut out for about 1 second. Then it would just heal itself.

I would take it home and could not reproduce the problem

On my third trip out, it was running fine until I hit a wake and pounded the boat (this might be unrelated) but then it started cutting out hard. I made it to port and took it home. I was happy to find that it was still exhibiting the problem.

I suspected the carbs so I popped a timing light on it (strobe is a great way to view fuel atomizing into the carbs) and much to my surprise I observed the strobe cutting in and out with the engine, so it looks like the spark was cutting in and out.

Because of the wave action, I suspected a loose electrical connection. Again, this might have been a coincidence but...

1. I disconnected the black/yellow cut out switch connector about the rectifier, no joy
2. I checked all the wiring for the timer/sensor but didn't see any loose wires or connectors.

Now I suspect that it might not be a loose wire at all but the power pack. My guess is that the electronics overheat in about a second and the power pack cuts out. After cutting out for a second, the semiconductors recover and spark comes in again and the oscillation continues.

Thoughts? Has anyone seen a power pack exhibit this behavior?

Thanks in advance!

 

[djwock]

Re: 1986 120 Evinrude Spark Cuts in and Out

Oh, one more thing, I recall the key switch being left in the on position for 1hr+ a few trips ago. I think I recall that this can be real hard on the powerpack.

Thanks in advance

Dave

 

[ezeke]

Re: 1986 120 Evinrude Spark Cuts in and Out

The black and yellow kill wire could be the problem: you should be able to check it with an ohmmeter and the battery disconnected.

I'm not sure that I understand your reference to the black and yellow wire and the rectifier, but they are not related. The kill wire is black, with a yellow tracer, and runs from the main engine harness to the powerpack with a single one wire amphenol plug in between.

I t would certainly be worth checking all of the ignition wiring from/to the powerpack for possible bad connections.

 

[djwock]

Re: 1986 120 Evinrude Spark Cuts in and Out

Hi Admiral

Thanks for your reply. What I meant is I disconnected the black/yellow 'by the rectifier'. The purpose was to rule out a shorted kill wire and an arcing key switch. With the wire disconnected, it still cut out.

I checked all the wiring but the weird thing is you can set your watch to the cut outs: 1 second on, 1 second off, 1 second on, 1 second off. If it was a mecahnically loose connection, it sure seems it woudl have to be one perfectly choreographed loose connection.

Have you seen a power pack exhibit this? I am ready to purchase one but I wanted to get an expert opinion on it.

Thanks!

Dave

 

[tashasdaddy]

Re: 1986 120 Evinrude Spark Cuts in and Out

make sure all the connections are clean, and no corrosion, that them apart to check. corrosion, can cause extreme resistance, and cause problems.

 

[djwock]

Re: 1986 120 Evinrude Spark Cuts in and Out

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