mercury 402 wiring problem

[trav44]

i have a 1978 belgian 402, i have a stray wire which is either yellow/black or vice versa, where would these connect to as its attached to the main loom coming in to engine and isnt attached at its end, so where would it connect to for choke and where for ignition killer, the reason im asking is because i have just replaced the starter solenoid and tried to fire her up, only to find the engine wouldnt stop turning over even when i pulled the key so had to undo the battery which was a bit scary as im a novice with electrics, the engine turned over but would not start, and i found the loose wire on inspection, any help so very gratefully received, and a wiring diagram which includes the yellow/blk or blk/yel will be so grateful.

 

[Maxz695]

Re: mercury 402 wiring problem

View attachment 172633 I spliced my 1979 40 HP harness when I had it. The black wire on the switchbox I believe should be as you see it grounded in the picture. There is also a grounded black wire to the attaching screw on the rectifier block. (It will not start without this attached) The salmon (ORANGE) colorored wire is the key switch kill wire from the switchbox. It also has the merc tilt kill switch connected to the same terminal. On my 70 HP the solenoind has a yellow wire on one terminal and a ground wire on the other but I don,t remember having that on my 40 HP. Your wiring harness may or may not be the same color codes as mine was though.View attachment 172634 The yellow with the black stripe go to the choke solenoid and the yellow with the red go to the starter solenoid

 

[ajgraz]

Re: mercury 402 wiring problem

A lot of diagrams here:
http://www.maxrules.com/mercwireindex.html

Though I'm not sure any correspond to your motor exactly, being that it's Belgian.

But if you look at the one for "Merc Model 70 HP........from Serial # 5579017 Wiring Diagram," it is probably what you need, minus one of the three coil/cylinders. It shows how the black/yellow wire hooks up for the kill circuit; ignition switch through harness connector to mercury switch and switchbox. On the motors before about 77/78 that circuit was an orange wire, so maybe your switchbox says "orange" where the kill wire should go.

(Sounds like your choke wire is yellow/black, which now that I see that seems like a dumb idea to make them look so similar.)

I hope you did not damage any of the electrical components by disconnecting the battery with it running. In future if this happens, disconnect the fuel line and let the carbs run out of gas instead.

 

[trav44]

Re: mercury 402 wiring problem

thanks, the engine turned over fine but would not fire, and as it wouldn't turn off at the key the poor old starter just kept turning over so it was the only thing i could think of to get it to stop and prevent the starter form burning out.

 

[carholme]

Re: mercury 402 wiring problem

trav;

Here is a link to the Clymer manual for your engine which is a later model 402 and as such, you would use the wiring schematic on page 230.

http://web.ebscohost.com/serrc/pdf?...931c-7faec223a630@sessionmgr112&vid=7&hid=118

Download it soonest as the link is short lived.


Gerry

 

[Maxz695]

Re: mercury 402 wiring problem

you should always choke the engine dead if it will not stop running

 

[trav44]

Re: mercury 402 wiring problem

thank you all very much, am going to have a try tomorrow, i think i should be running that loose blk/yel wire to ground/earth, will let you know how it goes.

 

[trav44]

Re: mercury 402 wiring problem

any idea why after changing the solenoid ( and yes i was very careful taking off the wires and fitting to new solenoid instead of taking all off at once ) the engine continued cranking even with key turned off and removed? am so struggling with this!

 

[Maxz695]

Re: mercury 402 wiring problem

It sounds like the key switch could be shorted. Esspecially scince you say you changed the solenoid. My key switch was sticking when I turned it over and the starter was staying engaged. Spray some lubricant into the key hole and work it several times to make sure the key is returning the the run position after the start position. The starter works off the solenoid and the solenoid can get worn enough to weld it in the start position but you say you changed it so that would lead me to believe the key switch is shorted ot sticking