1991 120hp Force L-Drive No spark

[cpsilvey]

Hi everyone. I am diagnosing a no spark situation on my 1991 120hp Force L-Drive and could use some guidance as to where to go next. Here is what I have discovered so far. With a DVA multimeter at the powerbox/switchbox I'm getting 224v on the blue/blue white stator lead pair and 24v on the red/red white pair (seems in spec). The trigger is outputting 2.4v on each pair at the switchbox (also seems in spec). I have isolated the ignition by disconnecting the 2 black/yellow kill wires at the terminal. When metering the coil output from the switchbox, I am getting zilch entering the coils. I tested at a few different ground points with the same results. I am wondering if the switchbox is bad or if something else could potentially cause the no voltage scenario at the coils. Thanks so much in advance for any help someone can offer!

 

[jerryjerry05]

You have the Mercury switchbox, if the stator is testing good
it can still be bad

The following is for the single pack and 4 coils.

Disconnect the black/yellow kill wires AT THE PACK and retest. If the engine’s ignition fires now, the kill circuit has a fault-possibly the keyswitch, harness or shift switch. Disconnect the yellow wires from the stator to the rectifier and retest. If the engine fires, replace the rectifier. Check the cranking RPM. A cranking speed less than 250-RPM will not allow the system to fire properly. Check the stator resistance and DVA output as given below:
Motors with Flex-plate Flywheel
	Wire	Read To	Resistance	DVA
	Blue Red	Blue/White Red/White	5000-7000 125-155	180V or more 25V or more
Motors with Cast, Vented Flywheel
	Wire	Read To	Resistance	DVA
	Blue Red	Blue/White Red/White	3250-3650 75-90	180V or more 25V or more
Motors with Red Stator
	Wire	Read To	Resistance	DVA
	White/Green	Green/White	500-700	180V or more
Red Stator Adapter
	Wire	Read To	Resistance	DVA
	Blue Blue(Each)	Blue Engine Ground	Open Open	180V or more 180V or more

Stator test.
Unit will not fire: Disconnect the black/yellow kill wire AT THE PACK and retest. If the engine’s ignition fires now, the kill circuit has a fault-possibly the key switch, harness or shift switch. 1. Disconnect the yellow wires from the stator to the rectifier and retest. If the engine fires, replace the rectifier. 2. Check the cranking RPM. A cranking speed less than 250-RPM will not allow the system to fire properly. 3. Check the stator resistance and DVA output as given below: Flywheel With Bolted In Magnets WIRE Read To OEM Ohms CDI Ohms DVA Blue Blue/White 5000-7000 2200-2400 180V or more Red Red/White 125-155 45-55 25V or more Flywheel With Glued In Magnets WIRE Read To OEM Ohms CDI Ohms DVA Blue Blue/White 3250-3650 500-600(a) 180V or more Red Red/White 75-90 28-32 25V or more (a) Encapsulated CDI stators will read 2200-2400 ohms from Blue to Blue/White. Red Stator WIRE Read To OEM Ohms CDI Ohms DVA White/Green Green/White 500-700 500-600 180V or more Red Stator Adapter WIRE Read To OEM Ohms CDI Ohms DVA Blue Blue OPEN N/A 180V or more Blue Ground OPEN N/A 180V or more

 

[cpsilvey]

Hey, thanks for the reply and the extra info! I will do all these tests after work today. Quick question though. I had originally suspected that the starter may be the culprit, though I don't have a timing gun to measure rpms. Is there any other way to verify that its spinning the flywheel at the right rpm?

 

[cpsilvey]

Well I do believe I found the problem. One of the magnets on the flywheel is almost fully dislodged and damaged, which seems to have damaged the stator as well. I'm guessing I need to replace both. Is it possible to repair the magnets in the flywheel? On first search, a complete replacement looks pretty dang pricey! My last reading on the stator showed the red/red white pair within spec, but the blue/blue white pair was reading 28.6 kilo-ohms resistance, which looks way out of spec.

 

[jerryjerry05]

I'd contact CDI ignition and talk to their tech team about the
results from a damaged stator.

Buying the flywheel is gonna HURT!!
I believe the 90 wheel is the same.
Buying a junk motor might be cheaper??

 

[The Force power]

I'd contact CDI ignition and talk to their tech team about the
results from a damaged stator.

Buying the flywheel is gonna HURT!!
I believe the 90 wheel is the same.
Buying a junk motor might be cheaper??

Last change in Fly-wheel was in 1986, so the '90 is okay

 

[cpsilvey]

Part number for the flywheel is 859241T10, which is still in production but worth it's weight in gold apparently. I'm surprised that there are no magnet repair kits for mercury....as far as I can see. Plus, there are no aftermarket options for the wheel. Watching ebay intently seems to be my best option. I found one on Shipwreck Salvage but they still wanted $400 shipped, which in my eyes is not much of a deal on a well used part.

 

[The Force power]

Last change in Fly-wheel was in 1986, so the '90 is okay

****CORRECTION*****
SORRY!!! the '90 will not work as this was prestolite ignition.
You need the fly wheel '92 thru '96