1978 Evinrude 35 hp Firing one side only out of power pack

I sure could use a little advice here.

1978 Evinrude 35 HP model 35853R

I have rebuilt the motor with all new ignition components. Under the flywheel I have a new charge coil and a new sensor. I have a new power pack and new ignition coils. I have good grounds on everything. I have installed an electric starter so it's spinning nice and fast (plugs out).

What is happening is that I have a hot spark on one coil only. The other coil has nothing. I have swapped out various plug wires and secondary wires and by process of elimination I can get the non working coil to spark just fine also if I plug it in to the working hot lead from the power pack. I cut out the plugs and soldered the wires directly to the power pack leads to eliminate a possible bad plug. It appears that I am getting voltage out of the orange/blue wire only coming out of the power pack and not the orange wire for the other cylinder. So I swapped out to another power pack but I have the same exact issue. That would appear to tell me it's not the power packs. I looked closely at the flywheel magnets and they look good but one side is noticeably stronger than the other side. I have adjusted the charge coil so that it's close and nothing is hitting or dragging.

Any advice would be very much appreciated by the experts on here!

Here is a photo of the mag plate with the coil and sensor. Do they look mounted OK? Can the coil possibly be mounted upside down with the wires on top and still work properly?

Hello? Anybody out there?

What if you had two power packs with the same problem ??

?---Weak magnets would be rare.----But you might try another flywheel as a test.

flyingvranch said:

Hello? Anybody out there?

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This has been discussed in depth at the other forum where you asked the same question. Many of us hang out at both places, and don't repeat ourselves. BUT, yeah I know, you are hoping somebody else will come along with the magic answer you are looking for.

racerone said:

?---Weak magnets would be rare.----But you might try another flywheel as a test.

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VERY rare. Almost unheard of.

It sound like pack is not being triggered to fire that coil. Since you swapped packs and problem stayed, swap the positions of the black and white wires, if problem goes to other coil its a trigger if not my bet is 2 bad packs.

I have another pack arriving today so I will test it. Thanks all for the advice!

faztbullet said:

It sound like pack is not being triggered to fire that coil. Since you swapped packs and problem stayed, swap the positions of the black and white wires, if problem goes to other coil its a trigger if not my bet is 2 bad packs.

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I just tried that and the trigger will fire a coil in one polarity but not the other. So it indeed sounds like a defective trigger? To be more precise, I switched the black and white wires and using the same ignition coil both times, it fires one way but not the other.

Either your reasoning is wrong, or I am not understanding what you are saying.

By switching the back and white wires as suggested by Faztbullet, you are manually changing the trigger sensor polarity to the power pack. This should cause the power pack to fire through either the orange wire or the orange/blue wire which it does. It would seem to me that this proves that the faulty trigger is not reversing polarity on it's on. I think I said it wrong in the earlier post.

It is physically impossible for the trigger to not reverse polarity. Trigger polarity is determined by which North/South magnet pole passes by first. Magnets on opposite sides of the flywheel are reversed and cannot be changed.

I spent all afternoon drawing this diagram just for you (and anybody else that is interested). If you understand basic electrical circuits with coils and diodes, it will make sense to you. Otherwise, I suppose I wasted my time.

If the opposite coil has quit firing and the one that was not firing has started the trigger is bad.

faztbullet said:

If the opposite coil has quit firing and the one that was not firing has started the trigger is bad.

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That statement would make sense, except that scenario ain't going to happen.

fdrgator said:

That statement would make sense, except that scenario ain't going to happen.

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Mr. fdgator, it sure happened in my case Buddy.

You know I have started a thread on another board because I needed help with an ignition issue that I am unfamiliar with and I wanted to get as many informed opinions as possible to diagnose the problems. You acted like that was a taboo and I was wasting everyone's time "looking for the magic answer" as you stated. It turns out that faztbullet did have an idea of exactly what was wrong and I am very grateful that he took the time to help me pin point the problem. That's was all that I was asking for.

All of your answers on this board to me have been crass and antagonistic. You have talked to me like I am a child. I am 60 years old and I have built 3 high performance airplanes and 7 boats from scratch. I know my way around, just not so much with outboard ignition parts.

My problem is now fixed thanks to all of the help that I have received and I very much appreciate all the other members who chipped in and helped me figure out this issue!

Yep, wasted my time.

Are you going to tell us what you did to fix it or not?

BTW, I have 21 years on you and 24 of them as a full time outboard dealer mechanic. I also went to television repair school to learn about electronics. Can't say that I ever built an airplane though.

I installed a new Evinrude sensor trigger and now I have a good spark on both coils. I have learned a lot from all of you (even you Mr. fdrgator) and I can finish up my first rebuild of an outboard motor. Hopefully I will get it buttoned up and running next week. I'll post some photos then. I guess it was just bad luck that I ended up with a faulty brand new Evinrude trigger the first time around. Thanks again!