1985 Johnson 70hp ignition problems

[dnr471]

1985 70hp J70TLCOS. Was running fine then completely lost the ignition. Motor would turn over but no spark on all 3 cylinders. I've isolated the Kill and it is functioning properly all the way back to the powerpack connector. If I disconnect the 3 wire powerpack plug from the wiring harness, the Black/Yellow-Kill wire on the female side of the connector is grounded when the lanyard is pulled, and open when it is engaged (as it should). On the same female side of the plug, if I jump the Brown(A) and Brown/Yellow(B) wires to isolate the Black/Yellow(C- Kill wire), It will start up and run fine. Once running, if I jump the the Black/Yellow(C-Kill wire) from the harness to the powerpack, it will not kill the engine, but it will retard the ignition. If I jump the Black/Yellow(C-Kill wire) to ground from the female side of the plug (the side the brown, brown/yellow, black/yellow go to powerpack and the black/yellow goes back to the kill switch) it will shut the engine off as it should. With the A/B jumped and the engine running, I tested the male side of the plug (Brown-A, Brown/Yellow-B, and Black/Yellow-C that go directly to powerpack) to see if the Black/Yellow was grounded and it was not. I was getting a hefty shock out of it and found that it has -100v on it coming from the powerpack.

I would not think that there should be 100v on the kill wire coming from the powerpack, but don't want to spend $130 on a new one just to test it. Can anyone help me out?

[Joe Reeves]

Keeping it simple, with all the wiring connected as it should be.... if you simply disconnect the black/yellow wire from the power-pack.... do you have spark?

[dnr471]

Basically yes, however I cannot simply disconnect it from the powerpack unless I cut the harness. The three wires that come from the powerpack, (Brown, Brown/Yellow, Black/Yellow) are in a plug (male side) that plug into the wiring harness plug (female side). The Black/Yellow-kill wire travels from the connector unbroken back to the big red plug connector. I would have to cut the Black/Yellow wire either in the harness or from the power pack. I essentially disconnected it from the powerpack by extending the Brown, Brown/Yellow wires in between the plugs leaving out the Black/Yellow wire.

When doing that I have spark and the engine runs.

[Joe Reeves]

Okay... As I understand the procedure you describe, in essence you did eliminate the black/yellow wire and in doing so... you did have ignition.

Also... With the black/yellow connected... and the ignition switch in the ON position... you DID NOT have ignition.

Now, if I understand correctly, that indicates that the ignition switch has a internal short... OR... the black/yellow wire is somehow shorted to ground somewhere between the engine and the ignition switch. It's normally the ignition switch.

To test the ignition switch..... considering that you have no ignition/spark with the black/wire connected normally.... remove the black/yellow wire from the ignition switch, then test for spark. If you now have ignition/spark... replace the ignition switch.

NOTE: It will be impossible to stop the engine from running with that black/yellow wire disconnected... You're most likely well aware of that though.

Let us know what you find.

[dnr471]

I started with the recommendations in the ancient Clymer and Johnson manuals and disassembled the remote to expose the ignition switch and kill switch. I removed the kill switch from the circuit and still no spark. I'm pretty sure that I removed the gnd (black) from the ignition switch as well as the kill (black/yellow) and still no ignition. I tested the voltage and continuity through each pole of the switch with the gnd's disconnected and everything rang out correctly. With all of these recommendations in the manual, I proceeded to the engine diagnostics which is what I posted above. When I tested the Black/Yellow with the lanyard connected and the "C" terminal was open to ground as it should be, and grounded when the lanyard was disconnected as it should be and I still didn't have spark, I checked the powerpack as they recommend.
Removing the kill switch and it runs would make it sound like the kill switch, however when I do that, I can't shut off the engine as you said. It also doesn't explain why all of the wire testing reads correctly, but it wont run. I'm going to go back to the ignition switch and start over, but do you know why when I do isolate the kill and get it running there is 100v on the Black/Yellow wire that comes from the powerpack that connects to that kill wire going back to the switch?

[Joe Reeves]

You're going off in some other direction with a Clymer manual.

Answer the two questions bluntly with a yes or no!

1 - Do you have spark with the black/yellow wire connected?

2 - Do you have spark with the black/yellow wire disconnected?

If #1 is a "No"..... and #2 is a yes.... replace the ignition switch.

[dnr471]

1- no
2-yes, but only if it's disconnected at the powerpack, not at the ignition switch.

My concern about the 100v on the kill wire at the power pack was due to information that I recently read and talked to a technician about with using a maintenance free deep cycle battery with my rectifier style system. It was stated that I cannot use a maintenance free battery with the rectifier because I can get overvoltage problems thereby burning up electronics and ignition parts. I'm concerned that I may have done something to the powerpack, causing 100v on the kill wire which is being fed back to the switch. I will change the switch since its only $25, but I don't want to change the switch and burn up a new one because there is a problem with the powerpack that is shorting the switch because it has 100vdc on it. I plan on changing the rectifier to a rectifier/ regulator and going with the old style Deka8 DPA24 battery to alleviate much of the concern with overvoltage once I get this problem fixed.

The J/E manual was very basic and said that if the Black/Yellow wire shows continuity to ground when the lanyard is removed, and open when connected then try a known working powerpack. The Clymer about a step up, but the simplified and indepth diagnostic information really came from the tech sheets provided by CDI electronics. They list troubleshooting steps and voltage/ resistance readings on every wire. What is not listed is if there should be any voltage on the Black/Yellow wire. My guess would be no because it is ground, but I want to confirm that before spending an additional $100 on the powerpack. Also, why would it only retard the engine if I reconnect the Black/Yellow wire after it is running and not kill it?

[Joe Reeves]

Replace the ignition switch to cure your ignition spark problem.

The engine's electrical/ignition system will build up it's own voltage on that black/yellow wire which is what you may be reading... enough voltage to knock you out of the boat. Whether it's AC or DC voltage I know not but it's engine generated.

Pertaining to DC voltage... do not ever apply battery voltage to the power-pack as that will destroy it.

If the engine runs properly with that black/yellow wire disconnected, there is nothing wrong with the power-pack.

If 100 volts had actually been applied to that black/yellow wire, there is no way it could possibly function. There's a lot of information in the manuals that will mislead you, causing a person to overthink and dwell into areas that will absolutely drive you nuts. No offense intended but I think you're right on the edge of the fence of the technical area that will have a tendency to lead you down that trail.

[dnr471]

The manuals were very misleading. The tech bulletin that CDI put out was very helpful, but I pretty much went back to plain ole thinking it out. After I got it running, I was just going through checking my theory. I expected that the Black/ Yellow wire coming from the power would be open, just waiting for the ground trigger to kill it, but I found out there was 100vdc on it the hard way. I'm just glad I didn't have the DVM set to Ohms or I'd have been out another few bucks. I'll change the ignition switch and let you know what happens.

[dnr471]

Well I got off early from work and was able to swing by the Evinrude dealer and get a factory replacement switch. Unfortunately that wasn't the problem. Still no spark unless I isolate that Black/Yellow wire at the powerpack. After running some things through CDI Electronics' tech support we've concluded that the problem is somewhere in the wiring harness since isolating the Black/ Yellow wire at the remote isn't allowing it to fire, but at the powerpack it is. I inspected the wiring in the remote and up to the jacket and the wiring "looks" fine. Back in the motor, the same harness wire up to the red female plug "looks" ok. A deep inspection of the wiring on the engine side of the plug harness revealed some potential problems. I split the wiring out of the loom and found that the insulation is brittle right at the entrance of the molded plug. With 100v on the black/ yellow wire, it would definitely find it's way to other wires that all appear to have small cracks in the insulation. I'm going to have to replace the engine wiring harness and hopefully that will be the fix.

[Joe Reeves]

Okay.... The black/yellow wire is shorted within the large RED electrical connector. Don't purchase a new harness.... simply cut and jump the black/yellow wire over the RED plug, putting a knife connector or connector of your choice in it.

Strange... In post reply #4, I listed how to test the ignition switch which should have shown that the switch was okay and the wire was at fault. Hopefully the dealer allows returns.

[dnr471]

I wish I could post pix on here to show you what I found. The insulation on all of the wires at the base of the plug is cracked, exposing the wiring. now after unwraping the tape to expose all of the wiring, I'm getting different voltages and grounds on wires I shouldn't. While the internal components of the switch may be working, they are probably over 30 years old, so I'm ok with keeping a new switch in there. With that being said, the wiring harness on the engine is original, so I'm ok with changing that too. I was able to get a factory OEM harness for $90 with s/h from Seaway Marine. Last thing I want to do is to get stuck 10 miles into the back country of Chokoloskee, broken down because I didn't spend a few more bucks on new wiring. I'll let you know the result next week.

[Joe Reeves]

***!.... That is amazing! I remember back in 1968 I think it was that OMC changed their supplier of wiring. The result was that the insulation of the wires (all of the wires) simply cracked and flaked away. It was a real mess, and you can imagine the nightmare it created for me and countless other mechanics. Your encounter sounds like a rerun (Twilight Zone?)

I agree that keeping the new ignition switch (30 years old) is a smart move as, in time, the switch (not all but many) eventually develops a intermittent short that allows DC voltage to jump across to that black/yellow wire that interferes with the ignition and eventually shorts out the power-pack. Also in agreement to replace the engine wiring harness obviously. You have a head on your shoulders... no Mickey Mouse short cuts! Storms in our areas and engine failures are a bad mixture.

[dnr471]

OK, so I've been kind of busy with work and now I'm in the middle of the caribbean on a 1000' cruise ship, but I did manage to do a few things. So the ignition switch was replaced, no change in condition. I changed the wiring harness on the engine side and I'm about half better than before. It still will not start with the system wired, but if I disconnect the black/yellow wire at the power pack it will start. If, once running I reconnect the black/yellow wire it will run properly, shut off properly with the ignition switch and/or kill the engine if I pull the lanyard. It just won't start with the black/yellow wire connected. I went ahead and replaced the kill switch (it was probably original as well). NO change. It will not start if it is connected, but it will run fine if I reconnect it after starting and the ignition switch off and kill lanyard work as designed.
What I'm finding is a potential to ground on that black/yellow wire of about 350 ohms back at the plug where it should connect to the powerpack. This is about half of what it was before I changed the wiring harness on the engine. Before, the potential was about 1k Ohm. I'm dreading that there is also a short somewhere in the main harness going back up to the remote. When I get back from vacation, I'm going to bypass the black/yellow wire all the way back to the ignition switch and kill switch and see what happens.

[dnr471]

I disconnected the black/yellow kill wire from the ignition switch and kill switch and completely bypassed it through the harness. Utilizing a new wire (not yet pulled through the hull) I connected one end directly to the powerpack, and the other to the ignition switch and it started right up. I re-connected the kill switch to the black/yellow wire on the ignition terminal and the other end to the ground wire/ remote body and everything works properly.
There is a partial resistance to ground on the black/yellow wire in the harness that will not allow the engine to start. While it is not ringing direct continuity to ground on an audible continuity tester, it does show resistance on an analog meter. My guess would be that either then harness chaffed in the hull, water is in the harness effecting the wire, or both. I'm going to pull the new wire through the hull so that I can go fishing, but I will undoubtedly search for a new boatside harness and completely rewire the ignition so that I don't have to worry about any additional problems.