1976 85hp no spark....???

[COLDSHOTAXEMAN]

O.K. ; another summer, another outboard. So, my 1976 Evinrude 85hp decides not to start. No spark. Get out the manual. Run some tests. I don't have the neon Tester they say you must use to diagnose the ignition. And from my e-b#y and internet searches, It seems finding one is next to impossible.
But I did do and ohms test on the stator assy /charge coils. And the timer base coils and they all pass.
So I replace the module. Still no spark. EXCEPT, I have spark when the plugs are out of the engine. But not when they are installed. (All coil leads are still removed from the plugs, to check spark). Weird huh?
Here's an even better one; Number two cylinder is the culprit! Only when Number two plug is installed, does the spark go away. Take it out, you got spark. Put it in, no spark. The other three plugs don't effect anything. Be they in or out. only #2 plug changes things. Remember, no plug wires are hooked up to the plugs during any of these tests. So, plug in, or plug out. It should not matter.
My only assumption on this is that the Compression on #2 is slowing the flywheel just enough to effect something in the Stator/ charge coils. But with four plugs installed. That should not make a difference either.
So my fellow boaters... Who's got something on this one????

 

[COLDSHOTAXEMAN]

Re: 1976 85hp no spark....???

So, here's a follow up. Still the same no spark issue as before. But, Actually #2 and#4 plugs once installed make the spark, on THAT bank go away. The odd Bank for cyl's #1 and #3 still have spark no matter what.
Anyway, so I got spark on at least two cylinders. So, I got some starting fluid, and gassed her with the ether. Which, just let say here and now,
I DO NOT RECOMMEND!!! As a professional auto mechanic myself, I think ether should be banned. It does serious engine damaged if not used properly, especially on two stroke motors, and, it's highly explosive and dangerous to mess with.
But, back to the point. After several crank overs and a couple sprays of ether, the engines lives again! It started and with the advance pushed up, stayed running. So I hook up the timing light to each cylinder while it's running, and I have good steady spark on all four cylinders. Why it did not have spark on #2 and #4 during cranking? Again, still a mystery. I have checked for this again since I got it running and the problem still remains.
But, for now, it's fresh gas. And carb rebuilds. I still think she'll leave me stranded on the water someday. But, ... that's another day...

 

[brianvolt7]

Re: 1976 85hp no spark....???

How were you able to tell that you had no spark when the plugs were installed? I have spark on my motor when I put the plug end against the block but cant get it to fire once inside. I know I have fuel and I think this may be the problem I am having. Is there a special tool I need?

 

[ezeke]

Re: 1976 85hp no spark....???

The CD ignition system on your engines requires 300 RPM to work. That's why you get spark with the plugs removed.

In order to get that speed with the plugs in, you need a fully-charged, powerful battery, immaculate connections and cables that are in excellent condition.

The cables are often the problem because they corrode inside the sheathing, creating resistance that cannot be overcome by maintenance.

Here's a link to a thread where the ignition system is the same as yours: http://forums.iboats.com/showthread.php?t=396825

 

[brianvolt7]

Re: 1976 85hp no spark....???

NICE, thanks for the heads up! I will check it out