Taco stopped all of a sudden while under power

Hi there, hopefully this is not a completely duplicate question.

I have a Mercury V-140 Saltwater (1B041534) and today while under power, I saw the taco drop all of a sudden.

When I power up the control box on with the key, the needle moves to 0 (when powered off the needle is slightly above 0) and my question is mainly around this behaviour.

If the needle moves to zero after being powered on, would this usually mean the guage itself is ok and there is more likely to be an issue on the engine end ?

Cabling look good end to end (control box is only 1 yr old)

cheers

Mark

Either lost signal thru bad connection or rect/regulator took a dump

cheers faztbullet, so you're indicating that the gauge is ok and that I should be looking on the engine side ? The rectifier and stator are next to the flywheel, is that right ? I was watching it when it failed and it was an immediate failure, so maybe I need to replace them ?

faztbullet said:

Either lost signal thru bad connection or rect/regulator took a dump

Click to expand...

I noticed today I have a brown wire (outlined in in the picture below) that is looking quite dodgy, any idea at all what it does and whether it could be related to the taco ? It does look still intact though. I have not taken the flywheel off yet, job for tomorrow and I'll check rest of it out.


This cable has a part code # 96455T18 Trigger Assembly what does this do ?


At this stage I'm trying to work out which wire I should be testing end to end. While it is grey on the sender end, there is no grey lead that is coming out of the end where the control box connects to the engine.


The black box next to it on the right, what might that be ?


Is the part that likely needs replacing under the flywheel ?


Sorry for the number of questions ..


Charge is getting to the battery by the way.

That the control module.. the rect/reg's is mounted between spark plug bank. looks like below and there is 2 of them

cheers faztbullet, I finally found a wiring diagram and now understand there are two of these and I'll switch the grey wire over to the other one and try it out.

and I'll repair that damaged brown wire, no idea what it's for yet though. The manuals aren't that detailed.

I reconnected to the grey wire on the 2nd regulator and now the tacho is working. I'm wondering whether I should be concerned about the other regulator, is it simple a spare ?

I also needed to order a new trigger as that brown wire was the heat alarm and it broke off right down to the trigger housing when I was trying to repair it. When the brown wire is disconnected , the engine idles at around 3000rpm and won't go overt that when under power. I guess this is the high temp control protection.

So next job is to get flywheel off and new trigger in.

Thanks for the tips.

cheers

Mark