Ignition problem 75hp

hello, I have a 75hp 4 cylinder 1986 Mercury that is not sparking on the bottom 2 cylinders. I was idling the engine last week and suddenly the motor went dead. A quick check found the problem. I have a maunal on order but I'd like to quickly fix the problem.

I checked the stator and resistance is in the correct ranges with no ground showing. I swapped the stator leads also and my problem remained the same(bottom plugs no spark.) With these checks I 'm assuming the stator is good, correct?

I understand that I can swap the trigger wires to check the trigger, but the searches I did do not have the same wire color wires from the trigger. My wires are; violet, white, brown, and white with a black stripe. My question is which wires do I swap to check the trigger.

I'm guessing that I have a faulty trigger box, but I replaced it last year and am wondering why it could have gone bad with maybe an hours running on the new box. Maybe a coil that isn't up to par?

Thanks for any help,

I

Posting your serial number will help. From mid 1985 on the 75 horse was a 3 cylinder so your motor must be a little older than you think.

Despite that, typically, loss of spark at two plugs (on a 4 cylinder) is indicative of a bad trigger.

A quick test, regardless of the colours of your trigger leads is to take the top two leads and put them where the bottom two leads go (and vice versa).

Of course the timing will be totally toasted but you can still turn over the motor and see where you are getting spark with the help of a timing light.

The "box" you replaced was the "switch box" I am assuming.

If you have a bad coil you usually only lose spark on that one cylinder unless two have gone at the same time.

Try the trigger wire swap and take it from there.

Serial number is A954203. Thanks for the info, I'll try the swap, mw