1990 Mariner 75 ignition fault

I just bought a boat with a 75 mariner as a non runner (got it at the right price) was told that they thought the stator was the problem.
when I got it home I pulled the flywheel and found all of the magnets had came off and two were broken.
I removed the stator and it checked out pretty close to where it should be resistance wise so borrowed a flywheel from a friend who has quite a few spare parts and after fitting it spun the motor to check for a spark.
I was only getting a spark on No.1 cylinder so I changed the trigger wires on the switch box and managed to get a spark on each cylinder proving coils were OK and hopefully the switch box as well.
To me that pointed to the trigger but my friend told me it was unusual for the trigger to fail so I borrowed a stator from him and got exactly the same result unfortunately he doesn't have a spare trigger unit.
Now looking for some advice if there is anything else that could be causing the problem.
hopefully the parts I borrowed are compatible my flywheel 9007C2 borrowed 9007C3 my stator 398-9710A14 borrowed 398-9710A28

Thanks in advance
Cam

Did you try resistance tests between the trigger wires?

That will quickly tell the if they are good/bad.

No, it won't tell if they are working correctly, but no continuity means it's definitely toast.

And agree that a bad trigger is rare, but not "unheard of".

Since you were able to get all the cylinders to fire by moving the one pair of good trigger leads that tends to indicate that the rest of the ignition is ok, in that the stator is providing power to the pack, storing it properly and releasing it to a plug when it gets "a trigger".

You should be able to find a used trigger if you don't want to immediately go the cost of new. The 75's and 90's used the same components and the 90 Merc just might be the most sold motor for a couple of decades - tons of them out there.

Thanks for your reply,
On my trigger wires disconnected from the switch box I am getting 2.330k ohms between white, brown & purple
and 1.169k ohms white, brown & purple to black.
All wires are open circuit to earth (getting about 20m ohms which quickly dissipates).
I am getting 14.35k ohms to earth from the switch box terminal where the black wire from the trigger goes (bottom right) which I wouldn't expect.

Just got myself a 2nd hand trigger that I was told was working, the odd thing is I am now only getting a spark on No2 cylinder (white wire).
I also made a DVA tester and all voltages were good apart from the trigger wires which were low on brown and white on my trigger and brown and purple on the replacement.
Getting a bit lost in what seems to be a fairly simple system.

Had a quick check yesterday and when I removed the black trigger wire from the CDI unit I got sparks on all 3 cylinders, admittedly they were random with No2 sparking a lot more than 1&3.
does anyone think this would mean the CDI unit is the culprit?


Cam

Got another flywheel with the same serial number as mine and now sparking on all 3 cylinders, checked a repair manual and found that post 1994 flywheels although physically the same size use a completely different centre magnet setup and are not compatible.