1976 Mariner Ignition Switch

jrbdjb

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Joined
Jul 11, 2016
Messages
15
I've scoured the internet looking for a replacement ignition switch for my '76 Mariner 115 with distributor ignition. Suddenly lost spark. Checking the wiring connections, I discovered the white wire at the ignition control box was had power with the key on, but when the key is turned to crank, the white wire loses power. The switch is pretty sloppy and needs replaced anyway. I can find hundreds for a magneto ignition, but so far zero for a battery distributor ignition. Does anyone have the Mariner/Mercury p/n for this? If not, why couldn't I use one for a mag system and wire the control to the accessory connection, leaving the mag connections unused?
Thanks
 

The Force power

Lieutenant Commander
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Feb 3, 2019
Messages
1,561
it may not be the switch

it could be that the "white" wire has only what they call "surface voltage" but not really enough to carry loads.
start at the source, inspect all wiring for corrosion/bad connections etc.
it being a '76 the wiring if original is bad

after verification of wiring being good, jump the switch terminals to see if works then, if so then yes the contacts in the switch are done.
http://boatinfo.no/lib/mercury/manuals/mercury_1965-1989_40-115.html#/312

a picture of your controls would help to locate a switch
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
23,850
They should be avail at a Mercury dealer. They are used for all motors, both ADI and battery powered CDI, for many years, at least in the 70's. They solder in to the wiring harness. On the ADI ignitions, the white wire is not present in the motor, but does power the gauges.

I would think Sierra would make one for a Mercury battery powered ignition, but since yours is likely inside the MerControl, an exact replacement is the best idea.
 

jrbdjb

Cadet
Joined
Jul 11, 2016
Messages
15
Appreciate the replies guys, and especially appreciate the link Force! Most of the wiring is in bad shape on this motor, the stator wires were actually crumbling. But with 120 psi compression on each cylinder +/- a pound or two this old motor is worth a little rewiring.
 

The Force power

Lieutenant Commander
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Feb 3, 2019
Messages
1,561
NOT A LITTLE RE-WIRING strip the harness completely back to the main plug & solder/shrink tube a new wire of required length and gauge. wire for wire/the entire harness
Fixed it right! and you'll save your self from a lot of misdiagnosing!
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
23,850
New Wiring harnesses for the engine (including the quick disconnect plug) are avail at many places on the web.
 
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