Thunderbolt ignition 120 hp force switchbox question/no spark

[ArmchairCruisers]

Ok fellas, I have a 99 force 120 4 cylinder outboard with the thunderbolt cdi ignition. I do NOT have any sign of power at any of the terminals on the switchbox with key on or off. All terminals test dead. O volts or near. The engine ran fine until I disconnected the battery to clean the terminals at the main starter relay. It appears I have reconnected all wires as they were, but I have lost fire. The reason I cleaned the terminals was a slow crank condition and that has been resolved. cranks like a beast but no fire. Can anyone tell me what terminals on a normally operating motor should receive power in the key on or off position? Its kinda driving me nuts. I do have a Clymer manual but the diagram is horrible and impossible to tell how power gets to the switchbox from the keyswitch or battery directly. Thanks in advance.

 

[pnwboat]

Are you sure it's a 1999 120 4 cylinder Force motor? 1996 and later motors do not normally use a Switch Box.

Regardless, check the Kill switch and the wiring to the Kill switch. To disable the Kill Switch circuit, disconnect the Black/Yellow wire from the Switch Box. See if spark returns.

The battery voltage is not used to power the ignition system. The ignition voltage is supplied by the stator. The only thing the battery runs is the starter, lights and radio, etc. You can disconnect the battery, wrap a rope around the flywheel and pull start the motor. It will run just fine.

 

[ArmchairCruisers]

No spark with black and yellow kill wire disconnected. Good point about battery. Yes I was not thinking clearly. Its not the rectifier as I pulled the yellow wires and still no spark. I did just replace the rectifier prior to this happening though. So what is most common item to change next? I do not have a dva meter.

 

[pnwboat]

You can check the stator windings with an OHM meter. To determine what the resistance readings, I need to know what color your stator wires are.

The stator produces the voltage to make the ignition system work. If it's not producing any voltage, then you won't get any spark.

 

[jerryjerry05]

Since it happened AFTER you cleaned the terminals???
​You didn't happen to cross the leads for a second????
If you did the rectifier/regulator was probably shorted.

Did you hookup all the wires on the battery?
Sometimes there is 2 on each terminal.

Under the dash might be a fuse panel that could have a blown fuse???

Look up DVA or Peak Reading meter on the search function.
It shows how to build one.

 

[ArmchairCruisers]

Thanks fellas, and I believe you are correct, I looked up serial number on your page and it appears to be a 92-95. Serial number is OE123xxx but I have seen other numbers indicating a different year. No, nothing got crossed not even for a moment. I bought the boat recently and knew it had a bad rectifier due to charred components in the clear window but the boat ran ok. After cleaning the terminals for slow start, I lost the spark. I figured the rectifier gave up the ghost and installed a new one. Still no spark but my tach now works and it did not before. Yesterday after I made this post, I found that the red wire going to the rectifier had a chafe in it it where it had vibrated against a sharp edge of the motor under the flywheel. I am pretty sure this likely caused the failure of the rectifier originally and may have taken out the stator when I cleaned the cables.

The color wires to the stator are:

blue
blue with white stripe
red
red with white stripe
yellow
yellow

I did perform the voltage test on the black with yellow wire with a standard volt meter and seemed to get pretty consistanly around 23 volts but with out a dva, im sure that's pretty unreliable.

One other noteworthy difference is I usually get a small spark when I hook up the battery small negatives, like I am charging a coil or capacitor. That no longer happens since I lost spark.

If you have a suggested course at this point, that would be great. Im not looking to easter egg this abortion, when there can be three costly parts in play. trigger, switchbox and stator. Thanks in advance.

 

[pnwboat]

Check the resistance between the Blue and Blue/White wires with them disconnected from the Switch Box. It should read between 3250 and 3650 OHMs (if it is an OEM stator). Next check between the Red and Red/White wires. They should read between 75 and 90 OHMs. The resistance test will at least verify if the stator windings are intact.

The resistance between the two yellow wires is normally around .6 OHMs. Almost a dead short. The yellow wires are for charging the battery only.

Also make sure that the 6 magnets under the inner circumference of the flywheel are in place and not broken or missing.