1971 Mercury 650 Ignition Switch...Lost in The Wiring..PLZ SAVE MY CAMPING TRIP!!!!!!

[SuperYooper]

I am supposed to go camping with my boat tomorrow but can't for the life of me find the answer to this:

1971 Mercry 650 (65 HP)
Serial # 299821

The guy wouldn't give up the ignition switch with the motor so I went out and got:

Sierra MP41070-2 Push to Choke ignition switch

Wires coming from engine:
Black------------Ground
Red--------------Juice
Gray-------------Tach Signal
Pink (slamon?)----Fuel Sener to Gauge
White------------NO WHITE LISTED
Brown-----------Reference Electrode MerCathode System
Yellow----------Starter Solenoid to Starter Motor

(Labels found on maxrules.com)

Wires Coming From Switch:
Black/Green Stripe-------NOT LISTED
Black/Yellow Stripe-------Shorting or top Circuit
Purple-------------------Ignition Switch to 12V positive
Yellow/Red Stripe--------Start Switch to Start Solenoid to Neutral Start Switch
Red---------------------Juice
Black-------------------Ground

All of the sites I can find on this switch tell me the colors are the same as Mercury.

Here is my problem...I have no clue what goes where since Sierra was comfident enough in my ability that they did not include a diagram with the switch...Grrrrr!

The red goes to red and black to black I assume. I have the Yellow/Red Stripe connected to the yellow wire right now and the engine turns over...kind of...It does very weak. The engine was just totally redone and the battery reads full juice. I am scared to turn it over too many times because I am very unsure of the wiring.

If you have any ideas please let me know. A camping trip without fishing it no camping trip at all! Save my camping trip please!!!!!

 

[Laddies]

Re: 1971 Mercury 650 Ignition Switch...Lost in The Wiring..PLZ SAVE MY CAMPING TRIP!!

Your 1971 650 is battery powered CD and the switch you bought is for a Magneto ign. Some one got you the wrong part, It's always easier to swap out switches with OEM parts.

 

[Chris1956]

Re: 1971 Mercury 650 Ignition Switch...Lost in The Wiring..PLZ SAVE MY CAMPING TRIP!!

Super, Your old Merc has the old wiring color scheme. You have some colors incorrect. grey is choke on the motor, Pink/salmon is ign killer wire, brown is tach signal, white is ignition power to the switchbox.

I think that magneto ign switch will work, but you need to connect it properly. The white wire on your motor needs +12VDC to have spark. so connect it to the purple on the switch. Salmon goes to Black/yellow. Brown is the tach signal. You do not have a MerCathode. Yellow goes to yellow/red. I will guess black/green is choke, since that is missing from your list, but you need to test to make sure. If so, it connects to grey.

 

[SuperYooper]

Re: 1971 Mercury 650 Ignition Switch...Lost in The Wiring..PLZ SAVE MY CAMPING TRIP!!

Thanks for the advise Chris. I hooked the wires up as you had stated and the starter engages, gives the motor one crank and stops. I turn the key again and hear a click. I am not sure if this is the starter being bad, the selenoid, or if I have something wrong in the ignition switch. I don' know which wires to check for juice. My next thought was going to be to jump the selenoid and see if it starts. This will tell me the starter is ok if that works right?

 

[Chris1956]

Re: 1971 Mercury 650 Ignition Switch...Lost in The Wiring..PLZ SAVE MY CAMPING TRIP!!

yes, Jumper the starter. The starter solenoid is grounded?
Next test for spark at the plugs, using a timing light. The only voltage should be on the white wire and red wires on the switchbox, plus the starter solenoid. No voltage on red and white wires = no spark

 

[SuperYooper]

Re: 1971 Mercury 650 Ignition Switch...Lost in The Wiring..PLZ SAVE MY CAMPING TRIP!!

I turn the switch on and can't even jump the selenoid. When I try to start it the starter engages with the flywheel for one turn then sits there. I try to start it again, it clicks. I tap the starter so it disengages, then try to start it, the same thing happens. I tried to trace the wires and could only come up with the grey being the choke, the yellow being the selenoid. The white goes to some panel on the front side of the engine with three other wires attached to it going in a vertical fashion. I am assuming as you said this one is for the spark.

It just seems I need more juice going back to the engine from the switch to power the starter. It really sucks because I have to leave in about 2 hours and I feel so far away from getting this done. I tried to test the wires but am apparently to stuipd to figure that out Can I not use the neg side of a battery as the ground for that? With the key turned on, I am not getting any juice to the whie wire or even the red for that matter. I think I screwed that up.

Is this jut a case of the wrong kind of switch? How can I check for spark it the engine won't turn over more than once?

 

[SuperYooper]

Re: 1971 Mercury 650 Ignition Switch...Lost in The Wiring..PLZ SAVE MY CAMPING TRIP!!

Off to the campground with no boat...boo!! I will be offline for a couple of days but any suggestions will be tried out when I get back Sunday! Thanks for those who have already helped. I hope the answer will be posted when I get back

 

[SuperYooper]

Re: 1971 Mercury 650 Ignition Switch...Lost in The Wiring..PLZ SAVE MY CAMPING TRIP!!

Update:

I pulled the starter and ripped it apart. I found that the bushings were pretty much shot. One had been worn so bad it was disconnected from the wire and the other three were worn right down to the wire. This makes me think your wiring schematic is correct Chris. We'll see how everything comes together when I get it all hooked up.

 

[Chris1956]

Re: 1971 Mercury 650 Ignition Switch...Lost in The Wiring..PLZ SAVE MY CAMPING TRIP!!

I would also inspect the battery cables and their connections. Corrosion can get under the insulation and eat the cable copper away.