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1977 55hp Evinrude, no spark (spark w/black yellow removed)...

A

ashpete02

New member
Hi guys,

Wondering if you can assist?

I have a twin engine 55hp evinrude 1977 setup. No spark on either cylinders with the black/yellow connected, spark is good with the kill wire disconnected.

Wiring loom from working engine, was put on the not the not working engine and engine fired once this morning, after this we were unable to get it firing and had no spark. By swapping the loom between engines, we believe we don’t have any wiring issues within the loom, nor issues at the switch, it would appears as though there may be a short to the black/yellow wire, within the motor wiring itself, is this possible? Is there anything you may know I should be looking for or some sort of test to help identify the issue whih appear to be at the motor..?!

Thanks in advance
 
Welcome to the Forum.
When you got spark from the original wiring set up, where did you disconnect the kill wire? At the power pack? What happens when you completely disconnect the wiring coming from the controls at the big red plug? Still no spark? Probably..... right? When did the problem begin? Anything noteworthy happen?
 
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Thanks for the welcome timguy!

I’ve taken this boat on with it’s existing problem and has been a problem since since it was brought into the family. It had never run right, was put into storage for 4 yrs... that’s why I’m hoping to sort it out.

We now get spark with the black/yellow disconnected at the powerpack (I presume this is the sealed unit with potted electronics), I’ve just done further testing and found that there is 0.1v, 100 millivolts, between the disconnected black/yellow wire and ground when the ignition is in the on position... (nothing when in the off position or when the loom is disconnected at the big red plug.. from the research I’ve done on these forums, this is probably the problem...not sure where to look or what to do to sort it out though..

Taking this all into account, when I swap this loom from the problem engine, back to the working engine from which it came, all works fine...the was our process of elimination, upon first connecting it earlier this morning it fired first turn over, but not again (it hasn’t fired at all before with everything else we’ve done) - not sure if heat has anything to do with it but it fired when it was cooler this morning, it’s now very hot...
We haven’t disconnected the harness/loom at the big red plug as that would not enable us to turn the engine over, in saying that, we get spark with the black/yellow disconnected...
 
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Does the working engine show 0.1volt too? My guess it's in the wiring to the control, but more likely in the control itself. There is a problem in the ignition switch. No voltage can enter this black/yellow wire into the power pack.....it will damage the pack and result will be no spark.
 
I’m yet to check for the same results on the working engine.... thing is that there is 2 controllers, one for each engine, neither will start the not working engine, that’s why we moved the working engine loom over to the not working engine, as I said it did start once but not again.. move this loom bak to working engine and starts up no problem... the good engine has worked consistently to my understanding...

Lets say I get the same reading on the working engine, the not working engine only sparks with the black/yellow disconnected... what else could it be? Surely we’d have no spark if the powerpack was faulty? So that rules out the powerpack? Could it be the wiring on the engine, if so any idea what could cause this issue!?
 
Ok, same result when loom is connected to the other engine, so it appears the voltage is coming down from the switch... starting to search the forum for what tests to do now.. is it possible both switches are just old.. it was all working in the arrangement at some point so I’m not yet convinced this voltage has damaged the powerpack on the working engine... hmm..

Update:
It was decided to disconnect all the dodgy DIY wiring the previous owners did as some of the insulation may have broken down on their crappy wiring (speaker cable etc)... the power connected now is only the engine supply cables...engine is now starting.. more testing to do but appears we may have found the problem, and a rewire of the boat will likely be done sooner than later.... will update with further results...
 
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Thanks, good figuring....some stray power or even ground getting back to the ignition system....possibly only while cranking. Try with ignition switch on, plugs removed, then crank with a rope......see if you get spark then.
 
In addition to and agreeing with Tims On Target advice, I'll put my two cents worth in here, hopping you don't mind Tim.

AshPete02 - Perhaps I'm misreading something here BUT...... if you're saying that with the black/yellow wire disconnected from the raised "M" terminal of the ignition switch, you're obtaining a voltage reading from that "M" terminal when the key is in the "ON" position... be advised that even a micro-volt being applied to that terminal will result in a damaged powerpack in a short period of time. If this is the case and the ignition switch is wired correctly, replace the ignition switch.

If removing the black/yellow wire from the pack enables spark, the pack is still okay. In my 30+ years experience with OMC, that has always indicated a shorted ignition switch.
 
Thanks, Joe....I'm just trying to fill in a bit here while you enjoy your retirement......you as well as many others here have guided me in a good direction.....I can actually make an honest living in this business now. This forum has helped so many.
 
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