1967 Mercury 650 Thunderbolt Ignition - Tachometer help needed

[tgp***]

I need help hooking up a tach for my motor

Tachometer is a NOS Faria 0-6000 rpm - has 6 settings all together with a setting for 12 pole outboards (#4 on the dial).

I found the following post from a search.

""Re: Tachometer for '72 1150
Most any aftermarket OB tach will work on that motor. You need to look to see if there is a brown wire on the switchbox, on the non distributor side. That is the tach signal wire and it is set up for the old Merc tachs, which no longer exist(or are hard to get). If so, that needs to move and connect to one of the yellow stator wires, at the rectifier. ""

did that... does not work

I have the wiring diagram so I'm certian I have the correct wires.

Also tried w/ wires connected the way it comes w/the brown wire connected to the switch box where it belongs. Did that does not work either.

Do I need a different tach? Do I have a different number of poles on the charging system? (I have never been able to find the information to confirm how many poles on the charging system) .

Thanks in advance

 

[Gomer50]

Re: 1967 Mercury 650 Thunderbolt Ignition - Tachometer help needed

You are on the right track,the tach needs 12 volts to work. Brown for your signal on one of the Stator wires going to your recitifier. White 12 volts and black negative.12 pole setting is correct.If it doesnt work try moving the signal wire over to the other wire coming from the stator on the recitifier.Hopefully your recitifer is good and your stator.

 

[tgp***]

Re: 1967 Mercury 650 Thunderbolt Ignition - Tachometer help needed

Thanks,

I'll try switching the wire over to the other stator that goes to the switch box. I'll let you know
what happens.

Would the motor still run if the stator or rectifier were bad?? The motor runs out fine.

 

[tgp***]

Re: 1967 Mercury 650 Thunderbolt Ignition - Tachometer help needed

Moved the brown wire to the other stator wire, still no go for the tach. It bumps when I turn on the key and start it but that is it, same as before.

What do I try next? Would the motor even run if the stator or the rectifier were bad??

 

[Gomer50]

Re: 1967 Mercury 650 Thunderbolt Ignition - Tachometer help needed

The stator/recitifier is used for the battery charging system.Start your motor and put a digital voltage meter on your battery if your battery shows 12.8 and rising then your rectifier and stator is working.On my 70's motors if the recitifier is blown my tach wont work.

 

[tgp***]

Re: 1967 Mercury 650 Thunderbolt Ignition - Tachometer help needed

Thanks, I will give it a go. However, I just ran out of free time.

Thanks again, I'll update when task is completed.

 

[tgp***]

Re: 1967 Mercury 650 Thunderbolt Ignition - Tachometer help needed

Quick question, how do I tell which thunderbolt ignition I have, it appears there are 5 types. from what I've been able to determine its type either III, IV, or V.

 

[tgp***]

Re: 1967 Mercury 650 Thunderbolt Ignition - Tachometer help needed

The stator/recitifier is used for the battery charging system.Start your motor and put a digital voltage meter on your battery if your battery shows 12.8 and rising then your rectifier and stator is working.On my 70's motors if the recitifier is blown my tach wont work.

Ok, did the test on the battery, and the battery charges, when the motor runs. The digital meter seemed erratic at times but I did have increasing voltage.

I can check the wiring agian, but I've done that several times. I could jumper past all wiring to go direct from the stator to the tach with the signal wire and see if there is a short somewhere.

Anything else I can try?>??