1994 Force Mercury 120hp No spark

[griggsmars]

Hello, I have a 1994 Force Mercury 120hp outboard on a 30' Suntracker pontoon boat. One day the motor just cut out while docking, and has yet to start again. I diagnosed that the problem was no spark. Since then we have replaced every electrical part on the motor and still no spark. Cranks over fine but no spark. Is there something in the controls or wiring harness that would stop the spark. Any assistance would be greatly appreciated. Thank you, griggsmars

 

[Redbarron%%]

Try disconnecting the rectifier/regulator (two yellow wires) and try again.
Then check the black/yellow wire to see it that kill wiring might be grounded. It is grounded with the kill switch off if the ignition is off. sometimes the wire gets shorted to ground.
I assume you tried all of the plugs. I like to use an induction timing light to see if there is current discharge to the plugs.
Also if there is a spark sometimes the flywheel key shears, but then you would still get a spark, but at the wrong timing.

 

[pnwboat]

Like Red Barron mentioned....the Black/Yellow wire on the ignition switch box is the ignition kill circuit. Disconnect it from the Ignition Switch Box and if it starts, then you either have a bad ignition kill switch, or a wiring issue. To stop the motor, you'll have to choke the carbs to stall the motor.

If it has no affect, look under the flywheel and check to see if all of the magnets are in place and intact. It's not uncommon for a magnet to come loose and cause insufficient voltage to the Ignition Switch Box to fire the plugs.

You mentione that you have replaced every electrical part on the motor....can you be a little more specific? Have you replaced the Ignition Switch Box and the Stator?

 

[jerryjerry05]

He said he replaced every electrical part so that leads me to
believe he pulled the flywheel???. Kill switch replaced?
Even a new stator can be bad???
outboardignitiondotcom has test procedures for your motor.

 

[griggsmars]

I agree that even a new electrical part can be bad, it's happened to me before. Did have the flywheel off to replace stator but not sure if the magnets were inspected thoroughly. Thank you

 

[pnwboat]

Try disconnecting the Black/Yellow wire from the Switch Box, crank the motor and see if it you get spark to the plugs.

Or you can test to see if the Black/Yellow wire is grounded. Disconnect the battery. Turn the ignition key to the "ON" or "RUN" position. With an Ohm Meter. put one lead on the Black/Yellow wire, and the other lead to a good clean spot on the engine block. It should read "OPEN", no continuity, no reading. If you read low Ohm's or dead short, then that's why you have no spark. The ignition Kill Circuit is engaged preventing any spark.

Normal operation is with the ignition key in the "RUN" or "START" position, the Black/Yellow wire is not shorted to ground. As soon as you turn the ignition key to the "STOP" position, you should read a dead short to ground.

If you're seeing a short to ground with the key in the run position, then the first thing to check is the "Kill Switch" usually on the dash or sometimes on the throttle control. You can temporarily by-pass the kill switch by simply pulling off one of the two wires on the kill switch.

 

[puffitu]

Had a similar issue and turned out the kill switch went bad

 

[griggsmars]

What is the kill switch? Also someone mentioned the trigger sensor. Any thoughts? Thank you, Mike

 

[griggsmars]

Thank you Pnwboat for reply. I do not have a kill switch on the boat, so I assume that it would be located on the throttle control? Thank you, Mike

 

[griggsmars]

I talked to my mechanic buddy. He says he only replaced the stator and module (voltage regulator)

 

[jerryjerry05]

Your kill switch is probably located on the shifter.
It usually has a cord/lanyard that can attach to the driver and if it gets
disconnected the motor quits.
Depending on the shifter the kill switch can be just a toggle switch
that is connected with the cord/lanyard to the driver.
Post a pic of the shifter(couple of different views?)
No trigger sensor on the 94 Force.

 

[griggsmars]

I don't believe that I have any kind of lanyard on the shifter, but I will get some pics and post them. Thank you

 

[Redbarron%%]

One way or the other if the black / yellow wire is grounded the ignition will not fire and you need to find where it is grounded (If that is the case)

 

[The Force power]

I don't believe that I have any kind of lanyard on the shifter, but I will get some pics and post them. Thank you

it is also referred to as a "man overboard" switch and can be a dash mount also

 

[griggsmars]

I have attached a couple pics of my Quicksilver controls to try to locate the kill switch. Any help would be great

 

[Redbarron%%]

Look under that little shelf below the key switch. Often the kill switch is a small toggle switch that is hooded so that a ring to the lanyard is trapped when the switch is up and the kill switch is letting the engine run. When the lanyard is pulled the ring flips the switch and kills the engine. Look for other switches like that

 

[griggsmars]

Thank you, I will look under there.

 

[griggsmars]

I just watched a video on you tube that showed what looked like my controls, and yup right under that hood was a switch. I'll look at it after work today. Thank you again!