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  1. #1

    Default 1979 80HP Mariner - won't shut off. Electrical quandary

    I have a '79 Mariner 80HP SR# 5385386038. I used the Mariner 800 parts manual for all part numbers that I replaced. No cheap Chinese parts, either.
    I replaced the internal wiring harness (414-3369) and it was a perfect match for the original harness that was all rotten. (See pics of the two)
    I replaced the stator and the trigger plate because their wires were all rotten.
    I'm using the old external wiring harness because it's in good shape. However, the wires to the key switch in the remote were crusty, so I peeled back some of the rubber cover and got to fresh wiring to resolder them onto the key switch.
    Confusion sets in because the external wiring harness has 7 leads while the internal harness has 6 leads. (see pics) SELOC manual shows both have 7 leads even though there are only 6 wires coming out of the internal harness. There is a white wire on the external harness but no white wire on the internal harness, regardless of the number of leads. See wiring diagram Iíve attached. Even the instructions for my CDI internal harness say to tape off the white wire if installed.
    Engine starts up and runs well but here are my problems:

    1. I can't kill the engine by turning the key to the off position. I have to use choke to kill the engine. This happened before I cleaned up the wires in the remote and after I cleaned them up. I also tried disconnecting the harnesses to kill the engine, but she still ran!
    2. Remote choke doesn't work. I cleaned up the choke switch and resoldered its wires. When I tested it for continuity, it works. Strangely enough, if I use the ďextraĒ pin with the white wire and the pin that has the grey wire for the choke, continuity checks when I push the choke button. But when I hook the tester up to a ground strap on the engine and the grey wire at the choke solenoid, there is no continuity when I press the choke button. Continuity checks between solenoid ground and a ground strap.
    3. While running the engine and holding a hose to the water tube (Lower unit is removed waiting on water pump), I got zapped pretty hard when I grabbed the key to try to shut the engine off (which of course, did nothing so I had to manually choke it to kill it).

    Questions:

    1. So what the heck is the 7th pin (white wire) on the external harness doing since it connects to nothing on the internal harness?
    2. Why is the Choke signal not making it past the external harness? or am I simply not testing it correctly?
    3. Why did I get shocked?
    4. Do I have one simple solution that could fix all these issues or do I have multiple problems here?


    For clarity to my current set up, I have the following notes:

    • I have an aluminum boat.
    • The engine is mounted on my boat with cables correctly running to the remote.
    • The remote is NOT attached to the boat. Currently, I have it back by the transom so i could be by the engine holding the hose to the water tube.
    • The battery cables are attached directly to a battery, not the selector dial.

    Thanks all for your help and any thoughts.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Last edited by IFlyMe; 08-14-2022 at 09:17 AM. Reason: Added question

  2. #2
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    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    Nice write up, good pictures. Welcome to the forum. Have you positively determined that everyplace that your black wire leads to, is grounded? When ignition switch is off, does it ground out the orange wire? Might be the ignition switch not doing its job well. Off would mean ground to orange. Test good solid continuity at ignition switch to ground at the black wire. Should be your solution.
    Last edited by timguy; 08-14-2022 at 09:54 AM.

  3. #3

    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    Thanks @timguy. I was hoping it made some sense.
    First time owning a Mariner/Merc and these are a bit different from my J-Rudes in the past. Mechanically simpler... I think :-) Definitely glad I found this forum. I have a feeling I'll find my way back here often enough.

    I can turn wrenches and put things together, but, this one has me a little baffled as I still consider myself a novice at the electrical stuff (i don't dare show pics of my soldering job at the key switch, LOL). I'm just barely functional on my Greenlee multimeter.

    As for the black wire being grounded, Engine side is good. Not sure what else to check outside the engine. Should the remote be fastened to the boat or grounded in some way? Currently, it's just setting loose (with all the cables and wire harness hooked up) back by the engine so i can do everything without hoping in/out of the boat. see pic with remote circled.

    As of later today, I'll be away from the engine for the next week or two, so I have time to gather some thoughts from everyone and then start digging when I get back to it.

    Do you happen to think that this would be the issue for the choke not working, either?
    What on earth is the white wire to the external harness' lead since there is no corresponding white wire on the engine side?

    Thanks again!

    Click image for larger version. 

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  4. #4
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    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    The white is the 12v+ to the tach socket on the front of your remote control. It picks up the 12v where it meets the choke wire under the choke button.
    I suggest pulling the switch again and checking the wires are not making contact.
    The grey wire/choke wire should not have continuity with block, it is the 12v to "make" contact to energize the solenoid.
    Engine not switching off, clean all connections to shiny and tight, check for continuity on all wires from switch to plug and on the wires on the engine side to the switch-box, the orange wire is the kill circuit, that's the one you need to check. And make sure the switch-box is well grounded.

  5. #5

    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    Thanks @haventaclue.
    One of the things Iím going to do first when I get back to my engine is clean all the leads in the harness (q-tips, metal polish, and drill has worked for this stuff in the past for me).

    switch block is def well grounded.

    how can I check to make sure a signal is being received at the coke solenoid by the gray wire so that I know if I need to replace the solenoid or not?

  6. #6
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    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    If you hook up the harness and press the choke button, you should hear the choke click and see the plunger move in to the solenoid

  7. #7

    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    Quote Originally Posted by haventaclue View Post
    If you hook up the harness and press the choke button, you should hear the choke click and see the plunger move in to the solenoid
    I do not see the choke plunger move which is why I want to see the the signal is even reaching the solenoid. Is there a way to test the gray wire. Should I see 12v if I hooked up one lead of the meter to the gray wire and the other to the ground then pushed the choke button?
    headed back to the engine to work on it this weekend. Hoping to resolve the issues.

  8. #8
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    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    Yes, there should be 12v at grey wire connection on the solenoid. If yes, solenoid bad. If not, check for continuity on socket pin to connection on the solenoid and through to key switch. To check solenoid, put 12v direct to solenoid.

  9. #9

    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    Quote Originally Posted by haventaclue View Post
    Yes, there should be 12v at grey wire connection on the solenoid. If yes, solenoid bad. If not, check for continuity on socket pin to connection on the solenoid and through to key switch. To check solenoid, put 12v direct to solenoid.
    nice! Thanks again

  10. #10

    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    Alrighty -
    New water pump parts installed and I cleaned up the connections at the harnesses and even spread the lead pins at their seams so they have a better connection. She fires right up and pumps water! Now I can start testing other things things like shut down circuit...

    I have 12V at the choke solenoid. Sadly, the solenoid is toast. Is there a way to repair these?

    Also disappointing is the engine will still not shut off with the key. I am able to jump ground to where the orange wire connects to successfully shut the motor off. So, I suspect the switch box is OK. Am I thinking correct here?

    I disassembled the remote and made sure all the connections appear correct at the key switch. So, I am going to replace the key switch. That means I have to do more of my favorite activity: Soldering LOL :-(


    Three questions:
    Is there a way to repair the choke solenoid?
    How do I test that I am getting a good kill signal from the key switch?
    How do I hook up the emergency kill switch that has the lanyard that attaches to the driver?
    My J-Rude remote was set up differently than this Merc/Mariner remote, so I'm not exactly sure where to connect the kill switch wires.

  11. #11
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    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    Q 1: None that I know of.
    Q 2:Check for continuity on the kill circuit, the orange wire.
    Q 3: There is no kill switch on that remote. You will need to install a separate switch to the switch-box. For illustrative purposes only Outboard Engine Motor Lanyard Kill Urgent Stop Switch Tether Lanyard For Marine | Fruugo IE

  12. #12

    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    Quote Originally Posted by haventaclue View Post
    Q 1: None that I know of.
    Q 2:Check for continuity on the kill circuit, the orange wire.
    Q 3: There is no kill switch on that remote. You will need to install a separate switch to the switch-box. For illustrative purposes only Outboard Engine Motor Lanyard Kill Urgent Stop Switch Tether Lanyard For Marine | Fruugo IE
    many many thanks, @Haventaclue
    that kill switch is darn near the exact one in my boat already that was installed by the previous owner for the J-rude. I’m just not sure where I hook it up: 1) Inside the remote to the key switch, or 2) take the wires all the way to engine, or 3)…?

    New key switch and choke solenoid on order. Should be here in a few days. Hope to have this thing wrapped up this next weekend. Fingers crossed!

  13. #13
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    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    Wiring very tight in the control. On my 1969 Merc800/80HP I took it all way to the engine and it is connected to the switch-box along with the orange wire.

  14. #14

    Default Re: 1979 80HP Mariner - won't shut off. Electrical quandary

    Quote Originally Posted by haventaclue View Post
    Wiring very tight in the control. On my 1969 Merc800/80HP I took it all way to the engine and it is connected to the switch-box along with the orange wire.
    Yup: Super tight space in there. I kinda figured that's what I'd have to do.

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