1980 Mercury 40 hp Key switch?

hi salenity

Seaman
Joined
Aug 1, 2007
Messages
52
I have a 1980 40hp electric start Mercury that Isn't getting any fire. I think It's a bad key switch but I can't find a diagram that show's what wire is supposed to be hot after the key is turned to the "run" position.

FYI the key WILL turn over the motor and activate the choke but if I turn the key to the "run" position the only Hot wires (other than the red power wire feeding the switch) Is a terminal that has 2 purple wires.

One Purple wire goes to the Tach and the other goes to the harness that plugs into the motor. This wire does not have a corresponding wire in the engine harness. In other words it doesn't go to anything. The male plug from the controls have 8 wires at the plug but the female side that goes to the motor was only made with 6 wires and 2 blank terminals (one is the Purple wire).

I guess if I was to bypass the key switch I could add a toggled Hot wire to the engine to use as the run switch?

ware would I hook a hot wire up to?
 

carholme

Rear Admiral
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Sep 4, 2010
Messages
4,845
Re: 1980 Mercury 40 hp Key switch?

What is your engine s/n as there are 2/3 and 4 cylinder 40hp engines?

Gerry
 

hi salenity

Seaman
Joined
Aug 1, 2007
Messages
52
Re: 1980 Mercury 40 hp Key switch?

C4CEAD61-B015-476F-8625-78B311174D23-8554-0000047ACBFE4310.jpg
No, this is it, Sorry that's the best pic of it I have
 

hi salenity

Seaman
Joined
Aug 1, 2007
Messages
52
Re: 1980 Mercury 40 hp Key switch?

It's push to choke & has the tether kill . It also has the no start in gear feature.
 

carholme

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4,845
Re: 1980 Mercury 40 hp Key switch?

OK. that is a Commander 2000, that is why you have the 8 wire to 6 wire problem. If you had the one seen in my previous post, you could hook it up directly.

Is this a new to you setup?

Here is a link to the Merc Controls manual where you can see the Commander 2000 and decide what you want to do.

merc controls newest manual - Download - 4shared

Gerry
 

hi salenity

Seaman
Joined
Aug 1, 2007
Messages
52
Re: 1980 Mercury 40 hp Key switch?

The boat sat for several years before I bought it and restored it but I'm pretty sure the motor and controls were original.

Thanks for the manual ill look at it and see if I can figure something out

Thanks
 

hi salenity

Seaman
Joined
Aug 1, 2007
Messages
52
Re: 1980 Mercury 40 hp Key switch?

OK. that is a Commander 2000, that is why you have the 8 wire to 6 wire problem. If you had the one seen in my previous post, you could hook it up directly.

Is this a new to you setup?

Here is a link to the Merc Controls manual where you can see the Commander 2000 and decide what you want to do.

merc controls newest manual - Download - 4shared

Gerry

I can't get that to open correctly? It wont show the pages for the Commander?
 

carholme

Rear Admiral
Joined
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Re: 1980 Mercury 40 hp Key switch?

Do you have Adobe installed on your computer as you must have it to read the file.

Gerry
 

Silvertip

Supreme Mariner
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Sep 22, 2003
Messages
28,758
Re: 1980 Mercury 40 hp Key switch?

You have a magneto ignition system which generates it's own power to provide spark to the plugs. Although the ignition switch may prevent the engine from starting, it is not for the reasons you think. A magneto system does not have a 12 volt input to it so there is no 12 volt line in the RUN position. The ignition switch has two "M" terminals on it that are connected to kill the engine (OFF position) or open to allow the engine to run (RUN position). "A" is accessory terminal which powers the gauges. "S" is the starter solenoid connection (START position). "B" is the battery connection via the engine harness. "C" is the push to choke connection.
 

oldman570

Lieutenant Commander
Joined
Mar 25, 2011
Messages
1,615
Re: 1980 Mercury 40 hp Key switch?

Do a web search for contunious wave whaler ingnition and it will get you the wireing for most ingnition switches for OMC and is about the same as the merc commander. It will atleast give you a diagram and most wire collors and a better understanding of how to wire your switch. Hope this will help if you can not get the download that Gerry has recommened. JMO
Oldman570
 

halmc

Petty Officer 1st Class
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Feb 27, 2008
Messages
231
Re: 1980 Mercury 40 hp Key switch?

You have a magneto ignition system which generates it's own power to provide spark to the plugs. Although the ignition switch may prevent the engine from starting, it is not for the reasons you think. A magneto system does not have a 12 volt input to it so there is no 12 volt line in the RUN position. The ignition switch has two "M" terminals on it that are connected to kill the engine (OFF position) or open to allow the engine to run (RUN position). "A" is accessory terminal which powers the gauges. "S" is the starter solenoid connection (START position). "B" is the battery connection via the engine harness. "C" is the push to choke connection.

Good points, all, and it might be well to note clearly that the ignition switch is more kill switch than ignition switch. When you turn the switch to the 'off' position, it kills the spark. If that 'kill' wire finds a ground (like through the kill tether, for example) it will snuff out the ignition. The kill wire on every mercury I've worked on is black with a yellow stripe.

BTW, it may go w/o saying, but I'll say it anyway: thinking that the lack of fire is a ignition switch might be wishful thinking since there are a boat load of other causes for lack of fire, and a bad switch is among the least likely.

Were I the list admin (a sobering tought, even to me) I would strongly encourage each question to include a history of the issue. In this instance, for example, it would help immeasurably to know whether it has always been thus, or whether the problem was encountered after normal operation. If the latter, incorrect wiring is ruled out. If the former, it's the most likely cause.
 

hi salenity

Seaman
Joined
Aug 1, 2007
Messages
52
Re: 1980 Mercury 40 hp Key switch?

Thanks guys the ground to kill makes sense I'll play with it more as soon as I get a chance.



Thanks all!
 

hi salenity

Seaman
Joined
Aug 1, 2007
Messages
52
Re: 1980 Mercury 40 hp Key switch?

Ok, I had a few minutes to play with it at lunch and I think halmc was spot on with the wishful thinking...
I checked the switch and it did ground the Black and yellow wire if the switch was turned off but has an open circuit wen in the on position.

I also chased the Black & Yellow wire to the CDI and found it was working like It should.
key off= ground
Key on = Open circuit

FULL STORY
I got this boat a couple of months ago and it had sat outside for a long time but it supposedly ran wen it was parked. I took the cover off and found it had some wires that had gone bad (CDI box and the wires going to the stator) I bought a "tested good" CDI off Ebay and spliced the bad wires on the stator to see if it can be saved.

I'm not sure why the wires went bad and most were fine but the insulation was crumbly on some of the wires

I'm now thinking I need to test the stator ...
What about the Mercury (tilt) switch do they go bad?
 
M

Maxz695

Guest
Re: 1980 Mercury 40 hp Key switch?

They can but not usually you can disconnect it to try to see if you have fire. The kill switch only kills the engine when tilted into the upright position. If it is shorted out then you will also get No fire
 

hi salenity

Seaman
Joined
Aug 1, 2007
Messages
52
Re: 1980 Mercury 40 hp Key switch?

I'm not sure I tested this right but I think the Stator is bad? Do you only test 2 of the 4 wires?

this is what I did I checked the ohms from the blue to ground and got 5.32 k ohms on my autoranging Ohm meter. I think that's inline with the 5000-7000 it should have.

The Red to ground only showed 47.8 and should have showed from 180-220

If I did this correctly the stator is bad?
 

hi salenity

Seaman
Joined
Aug 1, 2007
Messages
52
Re: 1980 Mercury 40 hp Key switch?

They can but not usually you can disconnect it to try to see if you have fire. The kill switch only kills the engine when tilted into the upright position. If it is shorted out then you will also get No fire

I tested it and it was OK
 
M

Maxz695

Guest
Re: 1980 Mercury 40 hp Key switch?

Keep in mind like the other day A poster had a problem with spark. Might not be your issue as you say you have a good key swtcu from your test. The key on the overbaord lanyard will in time wear out. even though t,s there it may not be opening up the switch enough to disengage the ground out that kills the engine. I found his issue by unpluggeing the boat harness and removing the yellow black terminal on the switch box to get fire. Fire was tested using a timing light to indicate we did or did not have spark.
 

hi salenity

Seaman
Joined
Aug 1, 2007
Messages
52
Re: 1980 Mercury 40 hp Key switch?

I was using a gap tester to check for spark . I went ahead and unhooked the Black and Yellow wire from the CDI and checked things again with a timing light. Still no fire.
 
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