Please Help With My Mariner 50hp Electrical Fault

[Excalibur5]

Hi everyone if you have read my previous posts you will know I got sold a duff engine that blew up at sea and was rescued by the coastguard! Well things have moved on and I now have a Mariner mid eighties 50hp 4 cylinder two stroke. Its all me and by friend could afford. Well its now on boat and would not start (no spark). Done a bit of research on here and disconnected the black and yellow wire from the switch box thats under the flywheel. Lovely spark and engine fires up great. Problem is cant turn engine off without either choking it or letting fuel run out(Not Good).

The black and yellow wire splits into two one goes to the mercury tilt switch and the other to the switchbox on the engine. So it will start with the connection removed from the engine switch box but wont turn off. As soon as you connect it up again the engine will not start as no spark at the plugs. On the quicksilver remote box there is a kill switch that seems to be working as when it is in the engine kill position no current can be found at the mercury tilt switch but when it is put into the run position there is voltage at the mercury tilt switch. The only puzzing thing that dont add up is that with the kill switch down there is about 0.3 volts at the mercury switch. Is my mercury switch at fault? Or the control box switch in ignition gear lever unit? I have fried my brain now trying to work things out! I even disconnected the mercury tilt switch to see if it made any difference but to no avail. I am getting very frustrated now as this is our second engine and only had three trips out in the boat one which ended in disaster! on the good side the engine seems to run fine. Its all a bit long winded I know but have tried to give you guys all the information . Any replies would be great.

 

[Barnacle_Bill]

Re: Please Help With My Mariner 50hp Electrical Fault

Check your ignition switch. There are 2 terminals marked "M". The black/yellow wire goes to one and the other goes to ground. With the switch in the run position there should be no continuity between the 2 "M" terminals. In the off position that black/yellow gets grounded and shuts the motor off.

 

[Excalibur5]

Re: Please Help With My Mariner 50hp Electrical Fault

Check your ignition switch. There are 2 terminals marked "M". The black/yellow wire goes to one and the other goes to ground. With the switch in the run position there should be no continuity between the 2 "M" terminals. In the off position that black/yellow gets grounded and shuts the motor off.

Many thanks for your reply i will do as you suggested next time i am at boatyard. I do have the old force engine's ignition switch as a spare and that could be used if the quicksilver ignition barrel is faulty.

 

[Excalibur5]

Re: Please Help With My Mariner 50hp Electrical Fault

Also why when i turn the ignition key to the off position does it not kill the engine ? Does the kill switch circuit have to be working properly for the key to turn the engine off?

 

[Excalibur5]

Re: Please Help With My Mariner 50hp Electrical Fault

Heres the deal i checked out the ignition barrel and existing kill switch. That circuit is only grounded when the key is in the off position which is as it should be. With the yellow and black kill switch wire removed from the engine switchbox it still checks out ok. There is no closed circuit in the loom to earth untill it gets reconnected to the engine switch box. So is it a loom fault or as I suspect a faulty switchbox? I have put a temporary kill switch in the circuit between the engine switchbox and the loom so i can kill engine for now.

 

[carholme]

Re: Please Help With My Mariner 50hp Electrical Fault

Excal;

What is your engine s/n?

Gerry

 

[Excalibur5]

Re: Please Help With My Mariner 50hp Electrical Fault

will look tomorrow carholme.

 

[Excalibur5]

Re: Please Help With My Mariner 50hp Electrical Fault

Serial number is 6542288

 

[Sunfish12]

Re: Please Help With My Mariner 50hp Electrical Fault

You shouldn't have any voltage on your kill wire, it's either coming from your ignition switch or a short on the kill wire. I doubt it's your switchbox.
I have my kill switch wired on a toggle switch, this way can never get accidental voltage from ignition switch.

 

[CharlieB]

Re: Please Help With My Mariner 50hp Electrical Fault

Disconnect the Black/yellow from the switchbox and attach one lead from your Ohm meter to the wiring harness side of the Black/yellow. Attach the other lead to the motor block/ground.

There should be continuity only when either the ignition switch is turned OFF or the Kill Lanyard is pulled.

If no continuity, start wiggling wires, somewhere anywhere the wiring harness flexes during operation of the boat you may find a chaffed wire shorting, or a broken wire poking out thru the insulation bumping against something and causing an intermittent ground which will kill the ignition.

 

[Excalibur5]

Re: Please Help With My Mariner 50hp Electrical Fault

Disconnect the Black/yellow from the switchbox and attach one lead from your Ohm meter to the wiring harness side of the Black/yellow. Attach the other lead to the motor block/ground.

There should be continuity only when either the ignition switch is turned OFF or the Kill Lanyard is pulled.

If no continuity, start wiggling wires, somewhere anywhere the wiring harness flexes during operation of the boat you may find a chaffed wire shorting, or a broken wire poking out thru the insulation bumping against something and causing an intermittent ground which will kill the ignition.

there is only continunity when the ignition switch is turned off or the kill switch is pulled. this is the case with our engine. but it wont start when the black and yellow isconnected to the switchbox on the engine casing. i have broken the circuit whih is always earthed down by putting another toggle switch in series. Starts first time. There seems to be continuity between the middle terminal of the switchbox and the earth terminal on switchbox.