You really need a DVA (Direct Voltage Adapter) for a multimeter

or a Stevens CD-77 to diagnose it properly.  If you have eliminated the

key switch and the emergency stop lanyard, using a standard multimeter,

(no DVA) you should see 1-5 volts AC coming from the triggers to the

switchbox when cranking the engine.

You should see 100-300 volts AC (no DVA) coming from the stator to the switchbox

when the engine is cranking. Use a fresh battery and remove the spark plugs

for the fastest cranking speed. I don't recall if that stator has

a low speed and a high speed winding or if it's a single

winding. Post or IM the serial number to me and I can look at the manual.

To "look" at the output from the

switchbox to the primary side of the ignition coils you need the DVA.

DVA adapter here.

DIY if you are handy with a soldering iron and a few components.

Another note..  You should use some form of spark tester

on the plug leads when testing. The switchboxes are prone to failure if the

high voltage from the coil gets back into it. if the plug leads are just hanging

in mid air, that high voltage has to go somewhere and it can find it's way back to the switchbox and kill it.

I do remember the red colored stators had an issue but can't recall if it was all of them

or just the ones on the V6's.

Triggers aren't really that prone to failure. It can happen, but

it's not too common. You can check the output of the trigger

and stator without the DVA because it is just AC voltage coming out of them.

The switchbox output is pulsed DC and where the DVA comes into play.

You can see it without taking off the flywheel. You can also do

an OHMs test to see if any of the stator coils are open.

IM me the serial number and I can see if there's any

service bulletins on it.

Oh yes. The old brittle Mercury wiring. I've seen a bunch of it

out here in the desert. I didn't think it was a big issue "back East"

where it's humid.

I'll bet you find the wiring bad where it goes into the stator.

If the insulation is rotted and the wire inside is green you'll likely

have to replace all the wiring.  Luckily there's not alot of it.

Here is the Mercury Factory Parts Catalog.

This is the same one I use but I go into it from the dealer port of the website.