1974 StarCraft Holiday Mercontrol - Engine runs with key in OFF position. Help please?

[Holiday16/85]

1974 StarCraft Holiday Mercontrol - Engine runs with key in OFF position. Help please?

Hello, I'm new to this boat and recently replaced the dash board. I had to unhook a couple wires behind the dash that go to the sump pump and a forward mounted spotlight the previous owner installed. I re-installed those wires guessing what posts on the aftermarket switches the PO installed. Had a few major 'sparking events' back at the battery tonight when I fired up the engine. I ran the boat last year with no problem starting and shutting off. Now, after the winter sitting in the yard and the dash replacement, the engine still runs when I turn the key to the OFF position. Can anyone guide me towards what to look for to correct this please? I also installed a tach in the new dash, plugged into the Mercontrol front tach plug ... not working at all. IS it possible that I connected wires under the dash that are creating this 'run in OFF position' situation?? Thanks for your help please guys.

 

[GA_Boater]

If you tell us what motor you're trying to turn off, we might be able to help. Assuming one of the myriad of Merc outboards?

 

[Holiday16/85]

Sorry ... it's a 1976 Mercury Thunderbolt 850 4 cylinder inline. Thanks

 

[Holiday16/85]

Anyone ... ?

 

[GA_Boater]

The "OFF" signal is from the key switch through the harness to the motor. I don't remember if it takes a ground or removing 12 volts to stop the motor.

 

[Holiday16/85]

Can the Safety Kill Lanyard wiring possibly be involved in this? When I turned the key off and the engine failed to stop, I pulled the lanyard from its post and it just kept running (idling). Wondering if I may have grounded the Safety Lanyard somehow?

 

[GA_Boater]

Since you worked on the dash and added or replaced the tach, disconnect the tach plug on the front of the control. See what happens.

What kind of "sparking events" happened at the battery?

 

[Holiday16/85]

I have been concentrating on the dashboard replacement and now finally getting to the motor inspection since last season. I have found that a few of the harness wires adjacent to the fuel pump and fuel line are losing their insulation. Apparently the previous owner knew this and tried to electrical tape and liquid plastic the whole mess back together. It seems there is significant destruction of the wire coverings right up to the lower cowl junction plug. 41 years of leaking fuel onto these wires and neglect no doubt. I have to 'switch gears' now and concentrate on finding an inner harness that plugs into the outer harness. Do you know where I might source a complete lower inner harness?? Thanks guys.

 

[GA_Boater]

A bad harness may be why the motor can't be shut off. Coincidence?

The internal motor harness - http://www.iboats.com/Mercury-Marine...view_id.335998

 

[Holiday16/85]

Thanks GA Boater, I ordered an internal harness (different part #), and hope to clear up the 'run when switched off' problem when installed.
Here''s where I could use some major help guys. The old harness wires are so broken down and covered in this liquid plastic that I cannot tell the original colors of the wires. I'm assuming the new harness will be color coded, right? So I 'd like to ask any of you guys that have a 76 850 4 cyl, if you would please take a look at your wires coming up from the internal plug, and give me a color coded outline or diagram of where each one terminates on the motor. This would be an incredible help as I cannot afford to burn up anything when instalking this new harness. I really appreciate if a couple of you 74-77 850 owners can verify the wire routing for me please. Thanks very much.

 

[GA_Boater]

Did you order a CDI harness or another brand? CDI has a set of instructions that may come with the harness and on their website.

 

[Holiday16/85]

Mercury brand. #73369A1. A couple pictures under the cowl showing the colors of the wires and where they terminate would be all I need.