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1991 Force 90 Prestolite ignition

trynhooker

Regular Contributor
Here's a strange issue and also a confusing statement in the CDI troubleahooting guide.

We had good spark all 3 cylinders. When in gear, #2 cyl spark starts dropping out, slowing down, goe right back to neeutral it fires normally again. Replaced #2 coil, customer said its worse.

In the guide it states:

NO SPARK OR INTERMITTENT SPARK ON ONE CYLINDER:
1. Check the stator and trigger resistance and DVA voltage (see NO SPARK ON ANY CYLINDER above).
2. If readings are good, disconnect stop wire from one pack. If the dead cylinder starts sparking, the problem is likely the blocking diode in the opposite pack.
3. If #2 on a three cylinder engine is the one not firing and the engine has a CDI stator installed, disconnect the Blue wire going to the #2 pack and see if the #2 cylinder starts firing. If so, reconnect the Blue wire with the Blue wire going to the #1 pack.

Pay attention to 3. as it doesn't make sense or I'm missing the point lol

The wiring diagram has a blue or brown/blue wire from stator to terminal strip, which connects to same color wire going to #1 pack (which fires #1 #2 cyl).
Wiring diagram shows blue or brown/blue wire from terminal strip to #2 pack, and no other wires connected to the terminal.

3. is saying disconnect blue wire going to #2 pack (which can only mean the blue or brown/blue wire) from terminal strip to #2 pack. This wire isn't being fed by any power source, so how could it make #2 cyl. fire)

Can anyone explain and I'm waiting on response from CDI as well.
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Try swapping packs around.
If #2 is the problem?? the swap makes #2 the extra lead.
Over on iboats . com try the Force forum.
 
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I swapped the Cdi's around yesterday. We still have the same problem on #2 cylinder. It sparked fine with my timing light running on the hose and didn't drop out when we put it in gear!
Customer took boat out later, started same problem again. It picks up and drops out of spark.

My only thought is it has to be in the CDI, the trigger is new and the #2 coil is new?
 
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