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Motor Starts, Won't Stop with Key or Kill Switch

L

leogallant

Member
[FONT=&quot]1975 Evinrude 40 HP[/FONT]
[FONT=&quot]Model: 40EL75C

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[FONT=&quot]Got this thing purring like a kitten, but have the old,"Starts with the key, but will not shut off when the key goes to the Off position" problem.

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[FONT=&quot]It did work correctly first, about 8 times, then it would do this thing where when you turned the key off, you could hear it rev a little lower, then turn the key on and get full revs. Almost like it was using the cutout switch.

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[FONT=&quot]Now, it doesn't even do that, just keeps running at full idle revs.

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[FONT=&quot]Brand new wiring harness on both the motor and to the console.[/FONT]
[FONT=&quot]Brand new ignition switch and kill switch. The kill switch never functioned right either.

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[FONT=&quot]I have tested every wire for continuity with tone on my multi-meter.[/FONT]
[FONT=&quot]I have tested both the new ignition switch and kill switch and they both function according to the continuity test for both the On/Off ignition switch positions, and the With/Without lanyard.

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[FONT=&quot]Could it be something wrong with the cutout switch?[/FONT]
[FONT=&quot]Again, starts up every time...[/FONT]
[FONT=&quot]Help! TIA[/FONT]
 
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I forget exactly on this year but doesn't it kill when a wire which terminates at the points....gets grounded. Perhaps that wire is detached. Just going on memory....they were changing ignition systems around at this time. Has exciter coils triggered by points and condenser, right?
 
It is NOT a vacuum cut-out switch problem. But it could be a wiring error. In fact, it most likely IS a wiring error. Begin with the wiring harnesses you put on. Are you positive you got the correct ones? It should have a blue wire and a blue wire with white stripe. They terminate at the coils at the motor end and at the ignition switch "M" terminals at the console. The motor kills when the ignition switch electrically connects those two blue wires together. I suggest you disconnect the lanyard kill switch, until you get the ignition switch working properly, then reinstall the lanyard switch correctly.

BTW, that motor has the Lo-Tension Magneto ignition. And 40EL75C is a Johnson model number, not Evinrude. But the electricals are the same. Perhaps the harnesses you bought are for something else entirely??? Can't tell from here.
 
I agree it's a wiring issue somewhere. Just curious why the cutout was trying to work and now it's not.

The CDI wiring harness I put on the motor is the correct one with the blue/blue-white wires to the coils.

However, the instruments cable (other harness) is not the correct one as NOBODY makes one anymore.

After reading around on forums, people were saying they were able to use the newer Red plug end version as long as you decipher which wires replace the blue/blue-white, which in this case is the Yellow-black/black to go to the M positions on the starter.
 
1. Save your energy. It cannot run unless the wires are connected to the points. The kill wire connections are made OUTSIDE the flywheel.

2. The vacuum cut-out is only activated in event of engine runaway, i.e. over-revving in neutral or out of the water. Is that what you were doing? In any event, the cut-out is not involved in completely shutting down the motor----if it is wired correctly.
 
So, Gator, the points and condenser are grounded to kill the motor, but where does the wire terminate? Is there a kill wire that goes up through the stator plate to the points?......like the straight magneto motors?
 
timguy said:
So, Gator, the points and condenser are grounded to kill the motor, but where does the wire terminate? Is there a kill wire that goes up through the stator plate to the points?......like the straight magneto motors?
Click to expand...

You have to consider how the Lo-Tension mag works. For the moment, let's ignore the stop circuit. There is a driver coil to generate electricity. The driver coil is double-ended, that is, there is a wire coming out of each end of the primary winding. Each end of the driver is connected to one of the points sets, along with a condenser on each. Also, at those junctions are the blue wires leading to the external spark coils. So, if the blue wires are not connected to the points, they are not connected to the external coils either, and it cannot run with the spark coils disconnected.

Enter the stop circuit. Sure, they could have run the stop wires up to the points, but why do that then the points/driver coil junctions are already accessible at the external spark coils? Much simpler and less bending/wear of the stop wires. Anyhoo, the deal is that they made the connections externally at the wires leading to the spark coils.

BTW, although the stop circuit shorts the points together, it also shorts the two ends of the driver coil together at the same time. It simply cannot run with the driver coil's ends shorted together.

Hope this helps.
 
fdrgator said:
1. Save your energy. It cannot run unless the wires are connected to the points. The kill wire connections are made OUTSIDE the flywheel.

2. The vacuum cut-out is only activated in event of engine runaway, i.e. over-revving in neutral or out of the water. Is that what you were doing? In any event, the cut-out is not involved in completely shutting down the motor----if it is wired correctly.
Click to expand...

That makes sense about the vacuum cutout switch, a safety feature when revs go haywire.

So, that means there's a loose/bad connection somewhere in the ignition wiring or a break in one of those wires?

If so, I can do a continuity test on all those wires.

As mentioned before, the key ignition checks out as to open/closed by key position when doing a continuity test on it, so it's gotta be wiring on the motor somewhere.
 
I would immediately suspect a mis-match between the red and black plugs, but you said you checked the continuity from end to end so I didn't mention it.
 
fdrgator said:
I would immediately suspect a mis-match between the red and black plugs, but you said you checked the continuity from end to end so I didn't mention it.
Click to expand...

Gator for the win! I re-looked at the harness tonight and son of a gun, it is a mis-match of the red and black plugs. The red end does not have a contact point to connect to the blue/blue-white stripe ignition wire which is circled in red in the pic. So it cannot ground out. Back to trying to find an instrument red.jpgblack.jpgharness, which may not even exist anymore...
 
Bought the matching red plug for the motor side and will splice it to the motor side harness. That should solve things...
Thanks for all the help, gents! Will let you know how it goes in about a week after the part comes in.
 
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