Changed stator & trigger. Now no spark.

[DJ_Allatoona]

1986 Mercury 75hp. It sat for many years and replaces my identical motor that locked up. I've got it running but have some occasional power-drop and electrical issues. I've been gradually replacing everything I can with parts from my old motor that I know are good.

Yesterday I swapped the stator and trigger and flywheel, hoping that was the cause of my electrical issues. Easy job and wiring both back up was uneventful. I followed the wire color guide stamped on the switchbox. While I was in there I swapped some other things, like the starter solenoid, the wiring harness, and the mercury switch. Just replaced every item and wire the same way the old one was.

I felt good because the wires on the old trigger were in horrible shape. Corroded and cracked and burned.

Tried to start it afterward and no spark. Turns over strong but no pop. And my cheap Harbor Freight spark tester showed no spark. It behaves as if the kill switch is thrown (happened to me before) but that is not the case here,

Is there something I have to do after swapping a stator/trigger to, I don't know...sync them up again, or make them work together?

Two odd things stand out: The switchbox says "WHT-BLK" where the bottom-most wire from the trigger hooks up. On the trigger I stripped from my parts motor, that wire is definitely YELLOW and BLACK. The same shade of yellow as the solid yellow wire that is connected above it. And on the trigger I replaced, that wire was solid black. The other thing that I noticed that the switchbox on my parts motor has a black wire coming out of the sealed interior of the switchbox that was grounded. The switchbox on my new motor does not have that wire, but every corner of it is grounded. Both are pictured below.

Sorry this is so long, but hopefully someone has some advice for me. Where to start chasing down this no-spark situation, and could it be related to my stator/trigger swap?

 

[The Force power]

Re-check your work, if it's correct; disconnect the "kill" wire from the switch-box to eliminate the wiring following.
I'm not sure anymore if yours a 3 or 4 cylinder?? I attached a schematic for a 4 cylinder for reference in case its the right one & you don't have one

 

[DJ_Allatoona]

Yes it's the 4-cylinder. Thanks for the attachment. "Kill" wire is the black/yellow? (Middle post on the stator side of the switchbox) If I pull it off and suddenly there's spark, that means the lanyard or mercury switch is kaput, right?

Curiously, the schematic you just shared, and a version of it in my SELOC book, both show that switchbox upside down from the position it's mounted in both of my motors. I don't suppose that matters...just an observation.

 

[GA_Boater]

You said one of the things changed was the mercury switch - Disconnect that thing 1st. If it starts sparking check the positioning and if the motor is tilted, lower it.

 

[The Force power]

It does not matter how its mounted, as long as the wires are connected to the proper terminals.
Yes have the BLK/YEL wire disconnected from the Switch-box and take a ohm or continuity reading from that wire terminal to GROUND if the there is a reading; disconnect the Mercury-switch/by-pass the lanyard switch (make sure your ignition-switch is set to on!!)

if there's STILL a reading, meaning a patch to ground, then that circuit has a short to ground.
It maybe easier to disconnect your boat harness to eliminate

 

[racerone]

Are all the terminals not labelled as to where the wires go on the switch box ???

 

[DJ_Allatoona]

They are, and I thought I wired everything right. But apart from removing and replacing the stator and trigger, and (ideally) wiring them both correctly to the switchbox...there's not a step that I'm skipping?

Good tips above about disconnecting the kill gadgets and re-testing. WiIl do that ASAP.

 

[The Force power]

You should verify...if the stator match-up with the switch-box (part numbers on them)

White wires will turn yellowish over time

just to clarify

1st. / 2nd.
The meaning of Mercury-wiring BLK/YEL

first color black & second color yellow
first color is solid & second color is the color of the line on it

 

[DJ_Allatoona]

I pulled the black/yellow wire from the switch box yesterday and suddenly had spark again and I could start the motor. I didn't have time to pull apart the remote control to see what's going on in there, but at least I know the stator & trigger swap wasn't the problem. Big relief!

 

[The Force power]

That's good, now work your way back to the front (boat-harness) to see what is causing BLK/YEL wire to ground.
as posted #5 but start with the Mercury-switch.

 

[DJ_Allatoona]

Update: I removed the mercury switch and threw it away. Then I traced the black/yellow wire back to the control box and found it in good shape throughout. Installed a new key switch and hooray! Spark returns. The bug was in the key switch. On to the next thing...

 

[The Force power]

Why did you remove it? you said the problem was the ignition-switch