HELP my 402

[jarand82]

so i got the thing to run but i am now having a wiring problem. i changed the control box because it was broke, and replaced it with a universal on. the old one had a "Tachometer Connector" which the diagram shows had three wires going to it, BLACK,BROWN, and WHITE. If I take the brown wire and "BRUSH"
it across a ground wile trying to start the motor it will start, but if I leave it disconnected or connect it to anything it wont fire. It goes to the orange wire on the switchbox witch is the kill wire. if anybody can tell me what to do with this wire i would be very happy.

 

[jarand82]

Re: HELP my 402

Cant anybody help me???????

 

[dtmc78]

Re: HELP my 402

Are you using a tach?
What did you do w/ the wht and blk wires that went to the old plug?
Just in case you don't have this.
http://www.maxrules.com/oldmercs/Wiring/1966ona/24.pdf
Did you try to connect it to the orange(salmon wire; see diagram)?

 

[jarand82]

Re: HELP my 402

I do not have a tach. all the wires are still hoked up to the original key switch.
I have a copy of the wiring diagram but i dont know what to do with the brown wire. like i said before, I have to "swipe" it across a ground in order to start the motor.

 

[jarand82]

Re: HELP my 402

I replaced the key switch thinking that i might have a short in it, but i still have the same problem. When i sit down and look at the diagram i keep coming to the same conclusion that i shouldnt even need the brown wire cause the salmon goes to the same place. Could it be ground to either the motor or key switch? could it be the ground to the switchbox? How would i add a ground to the switchbox since its plastic? I can add grounds till im blue in the face, thats not a problem. I just dont know where to start?

 

[DutchMerc]

Re: HELP my 402

Didn't the new box come with a wiring diagram? Do you still have the original one? The collors are a mercury-standard, but not universal. The only way to find out is to trace the wire back to the harnas, and convert the new (different) collors to the original collors, functions and positions on the harnas.

 

[dtmc78]

Re: HELP my 402

Looking at it again you are right. Something has to be shorted. You should be able to cut and cap all three wires. Ah? just for my own clarification, what year is your 402? '76-'78 brn goes to rectifier, '75 looks like it is bridged to the sw box.

??i shouldnt even need the brown wire cause the salmon goes to the same place??

I?m not sure what you mean about going to the same place. Same place on engine side or control side?

 

[jarand82]

Re: HELP my 402

when u look at the wiring diagram the brown wire goes to the "G" terminal and salmon goes to the "E" terminal. thats from key switch to engine harness.
Now at the engine harness it shows terminals "E" and "G" connecting together and the salmon wire going to the orange (Kill wire) on the switch box.

http://www.maxrules.com/oldmercs/Wiring/1966ona/24.pdf


I tried to separate the motor off the system today. I unhooked the harness at the engine and hooked a battery to the motor by itself to see if the problem might have been some ware between the harness and the key switch, but the problem was still there.

The question still remains. Why would I have to "swipe" the kill wire across a ground in order for the motor to start?

 

[jarand82]

Re: HELP my 402

Nobody knows how to fix this one?

 

[jarand82]

Re: HELP my 402

so i hooked the brown wire to a switch and mounted it next to the key switch.
when rolling over the motor all i have to do is flick the switch on and off and the motor fires right up. nobody knows why it is the way it is but this is the easiest way to have it.

 

[jarand82]

Re: HELP my 402

so i finally took the boat out for the first time today. Ran like a champ. ran for about an hour at half throttle then turned around and opened it up all the way back to the launch. lots of power. no stumble on accel. I've put about 500 into this motor in the last 2 years and this is the first time it ran back to the launch. I do wish I could figure out the problem with my wiring but I'm happy that it's running