125 hp Force outboard no spark going to #1 and #2 spark plugs?

[paulorlo]

Everything was working fine the last time I took the boat out. Motor was running good. Yesterday I started the motor and I could tell by the sound of the motor things were not the same. It started up, but when I pushed the throttle foward the motor would not go above 2500rpm and there was very little power. When I got home I bought 4 new spark plugs and the motor ran the same. I disconnected #1 and #2 spark plug wire with the motor running and no change in sound or speed. No spark to either spark plug. How do I isolate the problem? Could it be the ignition coils? Would two coils go bad at the same time? The CDI or power packs? Can I switch the wires around and see if #3 and #4 spark plug loose spark? The stator? underneath the flywheel as well as the other part responsible for spark. Could someone point me in the right direction. These electrical parts are expensive and I don't want to just swoop out expensive parts without testing them. Thanks in advance

 

[NYBo]

Welcome to iboats!:welcome:

My first thought was the CDI pack as I believe cylinders 1 & 2 share. But the gurus in the Force & Chrysler outboard section will be able to give you better guidance.

 

[pnwboat]

Like NYBo stated, it could be the CD Module that drives #1 and #2 coils. It could also be the stator winding the supplies ignition voltage to the CD Module for #1 and #2 coils.

Start off by making sure all the wires on the terminal strip for the CD Modules are making good contact and not broken. The wires for the ignition trigger are pretty fragile and are most likely to break. If you have any spade lug connections that have a small piece of black heat shrink covering the solder/crimp connection, the wires can break inside the tubing and the only thing holding the wire to the spade lug connector is the tubing itself, not the wire.

Make sure the Black ground wire from the coil mounting plate to the block is OK and making good contact.

You can check the resistance of the stator windings. There are two pairs of Blue and Yellow wires that come from the stator and supply voltage to the 2 CD Modules. Disconnect the pair that goes to the CD Module for #1 & #2 coils. Measure the resistance across the Blue and Yellow wires. You should read between 680 and 850 OHMs. If that checks out OK, then the next step would be to swap the wires between the two CD Modules and see if the problem moves to #3 & #4 cylinders. If so, probably a bad CD Module.

A word of caution when swapping wires or CD Modules around. There's a lot of wires and some that are the same color. Make sure you mark the wires, take pictures etc, before you disconnect them. It will possibly save you a lot of headaches and chasing around wiring problems.

 

[SkiDad]

I'm leaning more in favor that the stator is bad - when I replaced my #2 CD module this year it was not firing on 2 and 4 - and the troubleshooter at outboardignition.com said that no fire on the same CD is usually the stator but no fire on 2 different packs is usually a pack - CD to the right firesi followed the troubleshooters to figure this out by isolationg some other wires - like pwnboat said you need to do you tests as these parts are not too cheap. If you have any question feel free to shoot back b/c we have all done this a time or 2. I replaced my stator 3 years ago when I got the boat and this year a pack - it was 30 years old so I guess it was due.

http://www.outboardignition.com/support/176-5095.pdf

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[Jiggz]

No Title

One thing good about electrical problems especially with this Prestolite system, is you have identical parts you can switch around to troubleshoot without having to buy expensive spare parts. With that in mind, you still need to approach the problem carefully, logically and always start with the easy ones. "Target shooting" on which part could be faulty will eventually get you there but it can be very time consuming, expensive and sometimes frustrating. But worst yet, you could end up creating more problems than actually solving them.

So to start with, follow PNW's lead check to make sure the stator wires and CD module wires feeding #1 and #2 plugs are still properly connected. Then the next simplest test is to swap the stator wires (yel/blu) feeding CDM #1 to that of CDM #2, while disconnected, take ohms reading as previously mentioned. Obviously, if the reading is out of range there is no reason to continue switching the wires, but for the benefit of a doubt switch them anyways. If the problem follows, now do you not only have one proof but two that the stator is most likely faulty.

The preceding should very much cover your problems based on the symptoms provided. But if the problem persists, then it is time to check the trigger wires. Unlike stator wires, trigger wires are very hard to diagnose except to take resistance readings and making sure they are not corroded. But even then, it is very unusual to have two pair of wires to indicate same problem at the same time. Unusual but not impossible.

Here's a wiring diagram for your reference. You did not indicate what year the motor was, so I am assuming it is at least an '88.

 

[jerryjerry05]

Prestolite ADI Ignitions 1984-1992

General

Check for broken wires and terminals, especially inside the plastic plug-in connectors. We recommend that you remove the pins from the connectors and visually inspect them. Check the flywheel for a broken or loose magnet. Disconnect the kill wires from the CD and connect a DC voltmeter between the kill wires and engine ground, turn the ignition switch on and off several times. If, at any time, you see voltage appearing on the meter, there is a problem in the harness or ignition switch. At NO TIME SHOULD YOU SEE BATTERY VOLTAGE ON A KILL CIRCUIT. Visually inspect stator for burned or discolored areas. If found, replace the stator. If the areas are on the battery charge windings, it indicated a possible problem with the rectifier.

IF NO FIRE ON ANY CYLINDER: Disconnect kill wire AT THE PACK. Check for broken or bare wires on the unit, stator and trigger. Measure DVA voltage of the stator between the output wire sets. With everything connected, readings should be approximately 180 volts or more. Resistance readings between the stator wire sets range from 680 - 800 ohms. Disconnect the rectifier. If the engine fires, replace the rectifier.

NO FIRE OR INTERMITTENT ON ONE CYLINDER: Check stator and trigger resistance, trigger wire sets read approximately 50 ohms between the wire sets (DVA-5V or more), stator reads 680-800 ohms, DVA 180V or more from blue to yellow. If readings are good, disconnect kill wire from one pack. If the dead cylinder starts firing, the problem is likely the blocking diode in the other pack.

NO FIRE ON TWO CYLINDERS: If two cylinders from the same CD unit will not fire, the problem is usually in the stator. Test per above.

ENGINE WILL NOT KILL: Check kill circuit in the pack by using a jumper wire connected to the kill wire coming out of the pack and shorting it to ground. If this kills the pack, the kill circuit in the harness or on the boat is bad, possibly the ignition switch.

COILS ONLY FIRE WITH THE SPARK PLUGS OUT: Check for dragging starter or low battery causing slow cranking speed. DVA test stator and trigger.

HIGH SPEED MISS: DVA check stator voltage to each pack at high speed. If it exceeds 400 volts, replace the pack. Disconnect the rectifier. If the engine fires smoothly, replace the rectifier. Three and Four Cylinder Engines Using Separate Switch Boxes and Ignition Coils IF NO FIRE ON ANY CYLINDER: Disconnect kill wire AT THE PACK. Check for broken or bare wires on the unit, stator and trigger. Measure DVA voltage of the stator between the output wire sets. With everything connected, reading s should be approximately 180 volts or more. Resistance readings between the stator wire sets range from 680 - 800 ohms. Disconnect the rectifier. If the engine fires, replace the rectifier. NO FIRE OR INTERMITTENT ON ONE CYLINDER: Check stator and trigger resistance, trigger wire sets read approximately 50 ohms between the wire sets (DVA-4V or more), stator reads 680-800 ohms (factory) and 200- 300 (CDI/RAPAIR) DVA 180V or more from blue to yellow. If readings are good, disconnect kill wire from one pack. If the dead cylinder starts firing, the problem is likely the blocking diode in the other pack. NO FIRE ON TWO CYLINDERS: If two cylinders from the same CD unit will not fire, the problem is usually in the stator. Test per above. ENGINE WILL NOT KILL: Check kill circuit in the pack by using a jumper wire connected to the kill wire coming out of the pack and shorting it to ground. If this kills the pack, the kill circuit in the harness or on the boat is bad, possibly the ignition switch. COILS ONLY FIRE WiTH THE SPARK PLUGS OUT: Check for dragging starter or low battery causing slow cranking speed. DVA test stator and trigger. HIGH SPEED MISS: DVA check stator voltage to each pack at high speed. If it exceeds 400 volts, replace the pack. Disconnect the rectifier. If the engine fires, replace the recfifier