No spark on either spark plug

MBJJ2369

Seaman
Joined
Feb 11, 2017
Messages
69
Hello again everyone

I appreciate the help given to my earlier question. The boat ran fine for one or two trips, now I am having trouble again. I took it out the other day and it was running great until I shut it off. After sitting for a few hours, it was hard to crank and when it did start it ran rough. I brought it home and found there was no spark on #2 cylinder. I swapped the coils and now have no spark from any coil. I checked the ohms for the stator and trigger and they read within limits. The stator has four wires, 2 I blue and 2 green/yellow. I did the resistance check on blue to blue and get 736 ohms. I checked the trigger and on Orange to Green it is 50.4, on Red to White/Green it is 49.8. I checked the wiring diagram from the Seloc manual and made sure the coils were connected to the correct stator and trigger wires?

Is there any way to check the coils and if so how would I do that. Or do I need to buy new coils. The coils on it were only a year old.

Another thing I might should mention is the emergency kill switch does not work. When at idle and the clip is removed, I could here a difference in the motor, like it lugged down a bit, when the clip was secured it went to running normal. I checked the kill switch, when the button is pushed in there was fluctuating ohms, with the clip off it showed open. The kill switch is wired to each M post on the ignition switch.

Compression is 120 on each cylinder. When it was running on one cylinder the idle was fluctuating between 950-1010 RPMs.

The motor is a 1988 Force 50 hp 507Y88C.
Any help would be greatly appreciated
 

Jiggz

Captain
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Oct 23, 2009
Messages
3,817
First thing to do is disconnect the white wire from the engine terminal board that runs to the console. This white wire connects to the one of the M post on the ignition switch (kill switch is parallel to these two M post or wires) while the other M post connects to ground.

The system works like this. With the ignition switch in off position, the two M post are shorted together. This shorts the CDM's to ground and not providing power to the coils nor the spark plugs thus stopping the engine. The Kill Switch is normally open when set properly. And if activated it shorts the two M posts thus killing the engine.

When ignition is turned to on position, the two M post are disconnected or opened. Thus allowing sparks to the plugs and allowing the engine to run. By disconnecting the white wire from the terminal board, it allows isolating the ignition switch and kill switch. If the engine runs then you know where the source of the problem is.

Caution, if the engine runs with the white wire disconnected you cannot kill the engine with the ignition switch anymore. Instead you need to ground the white wire or place the ignition switch in the off position and touch the white wire back to each original connection to the engine terminal board. small jumper wires will be helpful in this process.
 

jerryjerry05

Supreme Mariner
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May 7, 2008
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The stator can read good but still be bad???
You'll need to do an output test.
​You'll need a special meter or an adaptor for an analog type meter.
You can use the search function on the Force forum and find the directions.

​The trigger is famous for broken leads.
​The wire breaks under the shrink wrap and looks good and can even be pulled on and not come apart.
​I just replace them(actually I replace all the connectors.

Also check for a broken flywheel key.
​Pull the plugs, long skinny screwdriver, insert in the top hole, turn flywheel (gently)until the screwy is pushed back out as far as it can go.
Then on the front of the motor, above the carb is a timing mark.
​It should align with a single mark on the flywheel. Should be close.
 

MBJJ2369

Seaman
Joined
Feb 11, 2017
Messages
69
Jiggz, I removed the White wire from the terminal block on the motor. Still no spark.

Jerry,
The flywheel key is good. The mark on the flywheel lined up with the screwdriver sticking all the way out. I have a dva adapter coming soon. If all the voltages check out then do you think its bad coils?
 

jerryjerry05

Supreme Mariner
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May 7, 2008
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17,923
2 coils going bad at one time??
​outboardignitiondotcom or cdiignitiondotcome
Both have test procedures.
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,817
Hello again everyone

I appreciate the help given to my earlier question. The boat ran fine for one or two trips, now I am having trouble again. I took it out the other day and it was running great until I shut it off. After sitting for a few hours, it was hard to crank and when it did start it ran rough. I brought it home and found there was no spark on #2 cylinder. I swapped the coils and now have no spark from any coil.

Have you tried re-swapping the coils or putting them back in original configuration to see if at least one cylinder will have sparks? Try that first and if one cylinder gets spark back, you know one coil is bad. Now why would there be no spark when you swapped the coils, it could be there is more problem in addition to the bad coil, i.e. loose trigger wire or a bad CD module. Yup, there are two separate ckts in one CD module and it is not unusual to have one go bad.
 

MBJJ2369

Seaman
Joined
Feb 11, 2017
Messages
69
I put the coils back in their original spot, still no spark one either one. Could a faulty trigger or stator short out a coil? With how the wires from the coils route behind them, I thought maybe there was a possibility that could be the problem. I checked the wires from the coils, there is no fraying or breakage. Is there any way to check a coil. I see the CDI chart lists an ohm value of 125-140 for the coil, I just aint sure where to check this.

I thought about getting new coils, stator and trigger, just so I know I have good parts to work with. Its a little pricey but cheaper than another motor.
 

MBJJ2369

Seaman
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Feb 11, 2017
Messages
69
Finally, got the DVA in. Checked the stator hooked it up blue wire to blue wire with DVA got a reading of 74.9V that was using the AC setting on the multimeter. Used the DVA to check the trigger orange to green and got .021V and the red to green/white read .024V this to was using the AC setting on the multimeter. Looks like I need to replace the stator and trigger.

Is there a way to check the coils? CDI shows the secondary should have 125-140 Ohms, but I don't know how to check this. Any help on this would be appreciated.
 

MBJJ2369

Seaman
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Feb 11, 2017
Messages
69
After doing some more reading I found out I should have had my meter set on DC. After doing that my stator readings are 355 Volts. The trigger readings are 2.1 Volts for the orange to green and 1.5 Volts for the red and green/white wires. still get no fire from either plug? Any suggestions would be great
 

gm280

Supreme Mariner
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Jun 26, 2011
Messages
14,585
I get the feeling you have some grounding issues going on.

You can check the secondary winding of the spark coils by taking one meter lead and insert it to the spark plug wire, disconnected from the spark plug of course, and the other meter lead to ground. You should be reading the secondary winding resistance. If that reads in the proper range, that isn't your problem.

I would go over each and every connection and clean them to shiny metal and tighten them good. Then try it again. JMHO

Report back here what those readings are and how things worked out.
 

Jiggz

Captain
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Oct 23, 2009
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3,817
OK, so far this is what you got:
Stator resistance check (Blu-Blu) - 736 ohms (range acceptable 680~800)
Trigger Resistance check (Grn-Orn) - 50.4 and (Red -Wh/Grn) - 49.8 (range acceptable 48~52)
Stator Cranking Voltage - 355 volts (acceptable range on this is 180V+ p-p)
Trigger cranking voltage - 2.1 volts and 1.5 volts (acceptable range is 0.5+ volts)

From the above you can surmised there is no problem with the stator and the trigger. I presume you have the "D" type ignition in your system (with separate coils and one CD module). Now you can also check the output of the CD module and it should be at least 150+ volts each leg. You can do this with each wire to ground. If you cannot get this output then the CD module needs to be replaced. But before doing so check the black grounding wire of the CD module to make sure it is connected properly and not broken.

If you get correct output voltage from the CD module, there is a good chance both coils are bad.
 

MBJJ2369

Seaman
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Feb 11, 2017
Messages
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gm280, I will check the resistance first thing tomorrow morning. I will also go over all the grounding connections to make sure they look good, shiny and tight. Thanks.

Jiggz, I have a C model motor. Two coils and no CD module. I guess the module is built into the coils.
 

Pusher

Lieutenant
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Sep 2, 2014
Messages
1,273
I think there's a kill switcg wire (mines above my coils on my 86 merc). I think if that's bad you don't get spark..... If you ran across my stator winding thread you'll know I don't know much about any of this.

Good luck!
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,817
OK. so if you have the "Non-D" ignition, then you have two CD-Coil Combo modules. And the kill wire should be brown for each combo module. Each wire goes to a separate terminal on the engine terminal block and continues on to the ignition switch on the dash. Each goes to the M contact connection of the ignition switch. In parallel with these wires (or two M contacts) is the stop switch or lanyard switch or Kill switch using blue and white wires.

For now disconnect the brown wires from the engine cowling terminal board. Turn the ignition switch to "On" position (DO NOT START!), check continuity or resistance between the M contacts or the blue and white wires from the Stop switch. It should read infinity or open or no resistance at all. If there is continuity then the stop switch needs to be reset. If it would not reset, then disconnect the blue and white wire from the M contacts. Read the M contacts again. It should read open. If not the ignition switch is most likely faulty. To validate, disconnect all wires from the M contacts and read resistance again. It should read open if not the ignition switch is definitely bad.

If from the preceding and the M contacts read open with all wires disconnected, then something is wrong with the white and blue wires.
If the stop switch reset and you do not have continuity on both M contacts with the ignition switch in ON position, The engine should start and run unless both CD-Coil modules are bad. Which is quite unusual but not impossible.
 

jerryjerry05

Supreme Mariner
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May 7, 2008
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If you have a tachometer??
Try unhooking it.
​WD-40 in the ignition switch.
​There also might be fuse under the dash that goes bad??
 

MBJJ2369

Seaman
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Feb 11, 2017
Messages
69
Jiggz,

When I open the dash panels i saw the previous owner had the kill switch wired wrong. One leg of the kill switch was wired to the M terminal with the white wire and the other leg of the kill switch was wired to the green wire on the choke terminal. The boat ran like this with both cylinders firing and the choke worked also. The kill switch would not kill the motor when pulled. it would bog down a little but the motor would not die.

I disconnected both brown wires that go from the coils to the terminal block. I turned the key to the on position, there are 2 wires coming from the kill switch both of them white one connected to the M terminal with the white wire the other connected to the M terminal with the blue wire. There is continuity in this configuration.

With the kill switch connected and the lanyard removed (like a man overboard), there is no continuity.

With the wires from the kill switch removed there is no continuity between the M terminal with the blue and white wires from the harness connected to the switch and the switch on.

With the blue and white wires removed from the switch, the M terminals there is no continuity.


I don't know if this matters, with the switch in the off position, there is continuity between the M terminals.


I did some testing on the kill switch disconnected from the ignition switch. With the lanyard in place and the button pushed in there is continuity between the two legs of the switch. With the lanyard removed (man overboard situation) there is no continuity between the two legs.


Jerry, this boat doesn't have a tach. Wished it did though.
 

gm280

Supreme Mariner
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Jun 26, 2011
Messages
14,585
MBJJ2369, A couple things you need to do. First, buy yourself an original factory shop manual for your engine. That will not only show you how everything works with the engine, but also a schematic diagram for your setup. Then wire the ignition switch like it is suppose to be wired. That way you will know first hand how it is wired. And the shop manual will explain everything you could possibly ever want to know about your engine.

Second issue. You can buy a cheap Tiny Tack off Ebay for a song. It will allow to read the engine RPMs without cutting into and wires or harnesses. And then you will know the engine RPMs instantly. And that little Tiny Tack works on all types of engines as well. Even lawnmowers. JMHO
 

MBJJ2369

Seaman
Joined
Feb 11, 2017
Messages
69
gm280,

I have a SELOC manual, checked the wiring diagrams for the ignition switch, motor terminal blocks, etc. Everything looks connected to the right places, Do you know if I can splice into the Tiny Tach wire so I can mount it on the dash. I have one but the lead is too short to reach that far.
 

MBJJ2369

Seaman
Joined
Feb 11, 2017
Messages
69
I put on a new kill switch. Everything tests out the way it should. Did a test of the ignition switch per the SELOC manual instructions, it tested good. Checked all ground points, cleaned with emory cloth to bright and shiny, still no spark.
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
gm280,

I have a SELOC manual, checked the wiring diagrams for the ignition switch, motor terminal blocks, etc. Everything looks connected to the right places, Do you know if I can splice into the Tiny Tach wire so I can mount it on the dash. I have one but the lead is too short to reach that far.

Answer; you sure can. The length of wire is only to allow you to reach places and still be able to read the meter safely. So go ahead and add on to it. But don't put on 20 feet of wire. Add on what you need and not go crazy with the add on. That wire merely picks up the spark energy via close proximity to the high voltage that goes to the spark plug and transfers that to the unit to be decoded into RPMs. JMHO
 
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