Ignition/Power Pack Problems? 1981 Evenrude 70 hp - please help

[tomwenz]

Great site of which I have read many threads trying to solve my motor issues. Need some additional help though to direct me in right direction.

All started with what I though was a bad ignition switch. Was receiving a shock when turning off key switch and motor would not stop running. Changed switch and it seemed to correct problem for a short while (20 starts maybe). Upon replacing the switch, have had motor issues I have been trying to resolve.

Engine would seem to run OK for for a few minutes and then suddenly bog down to what appears to be one cylinder (#2). In fact, had it out this morning for a test run and ran very smooth at low and high speeds for maybe ten minutes then crashed to a sputtering, coughing engine that barely got me back to the landing. Had it out yesterday also and it ran like crap from the start.

Here is what I have found/tested:

When sputtering, only cylinder #2 seems to be providing power. #1 and #3 are still getting spark but have no noticable impact in engine idling when plug wires pulled. Engine dies only when plug wire #2 is pulled. Because it ran great this morning (for a while) I think I can rule out fuel issues. Check all hoses, new gas, different tank/bulb, new plugs, good compression. No change (improvement) in performance when fuel is directly sprayed into carbs. Also cleaned out orfices in carbs although they all looked really good.

All of this leads me to believe this is an electrical issue. In addition, this morning after my ten minutes of good operation, the engine again will not turn off via key switch (+/- 20 starts after new switch was installed) and I received another shocked when attempting to do so. Please note I was having engine trouble while the iginition switch was properly operating in addition to now, when it is not.

My suspicion is the Power Pack but looking for some confirmation before spending the $ for a new one. Troubleshooting guide states I should remove the black/yellow wire from the Pack as part of determing where my issue exists. I can see no way to this, it is wired directly into the pack with its external connection being into a harness plug with 3 additional orange wires. I unplugged this harness plug but then engine would not start.

Am I missing something with how to disconnect the black/yellow wire from the power pack?
Could my failed ignition system(s) be somehow related to a bad Power Pack?
Anything else? Help would be much appreciated

 

[Daviet]

Re: Ignition/Power Pack Problems? 1981 Evenrude 70 hp - please help

If you have good spark, your power pack should be OK. What is your compression readings? You can use jumper wires to reconnect the wires in the wire connector to run your engine. You can go to the CDI website and look up your engine and use their troubleshooting guide to help you find your problem.

 

[tomwenz]

Re: Ignition/Power Pack Problems? 1981 Evenrude 70 hp - please help

Compression was around 115 to 120 for all three cylinders. Will try jumping the three orange wires through the plug allowing me start motor without ground to help further troubleshoot (should really have thought of that!). Thanks for the help.

 

[durban]

Re: Ignition/Power Pack Problems? 1981 Evenrude 70 hp - please help

the black & yellow wire is a wire that cuts the supply to the stator it is connected to the ignition or safety switch if you have one in your controls , so the shock you getting & spark loss is because of that wire , iam not an electrician , experience tells me this . so what you have to do is connect the motor direct to the starter motor & connect that black & yellow wire to the power pack . pull the red plug out from the ignition main harness & start it direct from the battery , the problem should go away . you can do this as a check only .

 

[tomwenz]

Re: Ignition/Power Pack Problems? 1981 Evenrude 70 hp - please help

Ok, so as per the CDI troubleshooting guide under "Engine Will Not Shut Off", I disconnected the black/yellow wire from the power pack plug harness and shorted it to the engine ground. This caused the engine to kill so I presume this means it "caused the pack to stop sparking" and therefore confirms the stop circuit has a fault.

In addition, I also started and ran the engine with the main harness red plug disconnected as suggested by "Durbin" and noticed no change in low idle (back yard) engine performance - still only really firing on #2 with weak contributions from #1 and #3. It looks however that I getting a good strong, white spark from #1 and #3 plugs. Can I then presume that the stop circuit fault (another bad ignition switch?) is not at all related to the engine performance issues? Since I am now on my second iginition switch in a short time span is there potentially something else going on with the electrical system that is blowing them out or did I just get unlikely and bought a new ignition switch with a very short lifespan?


I did notice while working on the engine tonight that there was some arcing behind the power pack at it's ground connection on it's lower fastening bolt. Is this normal?

Please recall from my original post that:

- upon installng the second ignition switch the kep stop worked just fine (for a while).
- The engine was performing poorly even when the new ignition switch worked.
- The engine ran great with all cylinders popping Sunday morning for 10 - 15 minutes before it crapped out again.

 

[tomwenz]

Re: Ignition/Power Pack Problems? 1981 Evenrude 70 hp - please help

Ok, so as per the CDI troubleshooting guide under "Engine Will Not Shut Off", I disconnected the black/yellow wire from the power pack plug harness and shorted it to the engine ground. This caused the engine to kill so I presume this means it "caused the pack to stop sparking" and therefore confirms the stop circuit has a fault.

In addition, I also started and ran the engine with the main harness red plug disconnected as suggested by "Durbin" and noticed no change in low idle (back yard) engine performance - still only really firing on #2 with weak contributions from #1 and #3. It looks however that I getting a good strong, white spark from #1 and #3 plugs. Can I then presume that the stop circuit fault (another bad ignition switch?) is not at all related to the engine performance issues? Since I am now on my second iginition switch in a short time span is there potentially something else going on with the electrical system that is blowing them out or did I just get unlikely and bought a new ignition switch with a very short lifespan?


I did notice while working on the engine tonight that there was some arcing behind the power pack at it's ground connection on it's lower fastening bolt. Is this normal?

Please recall from my original post that:

- upon installng the second ignition switch the kep stop worked just fine (for a while).
- The engine was performing poorly even when the new ignition switch worked.
- The engine ran great with all cylinders popping Sunday morning for 10 - 15 minutes before it crapped out again.

 

[oldcatamount]

Re: Ignition/Power Pack Problems? 1981 Evenrude 70 hp - please help

The arching behind the pack is not normal. Take the pack off, look for a crack in the back (or a chaffed wire). Clean the mount holes and the ground connection. Be sure the bolts are tight when re-installing the pack.