86 mercury 75hp intermittent spark

Hi I recently got a boat with a 75hp mercury outboard on the back. Was told it has a slight miss and needed to sort it out.
I have done compression test and all were 142-151psi.
have done a spark test and here is what I found.
Only cylinder number 1 was sparking. I tested each plug and lead and all sparked when plugged on coil number 1...
then randomly i got spark on 1 and 2...
I thought it was the coils so Pulled them off and rearranged the order. I tried the bad coils in the good coils position and the coils sparked so the problem is before the coils

what's the most likely problem? The stator, trigger or power pack? And how do I check which one is faulty? Dva and Resistance check the trigger and the stator but How do I test the power pack?

I'm leaning towards a bad trigger coil. You can verify that with an ohm meter. You'll need a wiring diagram to see which pair to test.

Jeff

Thanks a mechanic friend of mine said the same thing so I will get a meter on it and check it out I've been trying to get a dva adapter to test the voltage on trigger. My tutor said to read peak value use hold function on the multimeter so I will give my multimeter a try see if it gives me a good reading.

A simple ohm meter test will tell you if the trigger is okay. It's just a bunch of simple circuits reading a magnet flying by in the hub.

I heartily agree with using a DVA meter to troubleshoot these systems, however. Mine has become my favorite tool!

Jeff

Might be some help if you go here to see what I did: http://www.marineengine.com/boat-fo...68-Yet-Another-Merc-40-2-Stroke-With-No-Spark

Might be some help if you go here to see what I did:
http://www.marineengine.com/boat-fo...68-Yet-Another-Merc-40-2-Stroke-With-No-Spark
There you can find links to a CDI manual for diagnosing electrical problems.
If you have an ohm meter and a DVA, you can pretty much figure out the problem.

Pulled trigger off and One wire was falling apart so I soldered new wire on it and retested resistance and results were good so I put trigger back on
Now 3 and 4 are sparking so the trigger was causing that issue..
But now i only have 134 and intermittently on 2
I checked the coils again by moving them round and still get spark on 134
I switched the trigger wires around to fire the opposite cylinders and nothing happened still only spark on 134... so it's the power pack I've ordered a new one fairly cheap off aliexpress will confirm in next couple weeks