No spark on either spark plug

[MBJJ2369]

gm280,

Does it matter what size wire I use for this?

 

[jerryjerry05]

I'm redoing the boat.
I'm installing a single Mercury.
The tachs I have won't work on the new motor.
You pay shipping, I'll give you one of my old ones.
My tachs are from a 1988 85hp Force.
Send me a PM with your e-mail if interested.
​They're not in perfect shape but were working when I removed them.

 

[Jiggz]

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.

-That is correct with the kill switch (KS) wired wrong it will not kill the motor when activated. The correct wiring of the kill switch is to be in parallel with the two M contacts. The ignition switch in normal off position, the M contacts shorts together killing the engine by shunting the CD-coil modules.

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.

- This is not normal. With the ignition switch in ON position, there should be no continuity assuming the KS is not activated (man overboard) meaning the pin is in place. There is continuity but you never mentioned if the kill switch is activated or reset.

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

- This is not normal! With the kill switch activated (man overboard) there should be continuity. With continuity the engine shuts down everytime either from the ignition switch being turned to OFF position or the KS being activated (man overboard)

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.

- This is normal indicating the ignition switch is properly working.

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

- Again indicating the ignition is working properly. Assuming it is in ON position.

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

-Again, this is normal for a properly working switch.


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.

-Try reconnecting the brown wires in the engine terminal board and all the rest of the wiring correctly except for the kill switch. Keep both wires from the KS disconnected. Try running the motor again and post your results.


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

Post your results with the KS disconnected.

 

[jerryjerry05]

I'll ship the tach tomorrow.

 

[MBJJ2369]

Jiggs,

With everything hooked up except the kill switch I still did not get any spark from the coils

 

[MBJJ2369]

I'll ship the tach tomorrow.

Thanks Jerry

 

[Jiggz]

Jiggs,

With everything hooked up except the kill switch I still did not get any spark from the coils

It's time to get a new or even old known working CD-Coil module. Start with one module first and see if you'll at least get one plug to spark. The bidding store has some for a reasonable price. Just make sure it's a known working unit. If you get spark thereafter, you know both modules need to be replaced. If you do not get any spark still thereafter, then the problem is somewhere else. And you could go back to the stator/trigger units.

 

[MBJJ2369]

I will order a brand new one. Found a place that has em for about 75 bucks. I will put it on and see what happens. Which piece would be best to work on next if I still dont get spark, the stator or trigger.

Do you think it is possible for the incorrect wiring of the kill switch to the ignition switch could have shorted the coils? Is there anything else that could cause them to fail?

 

[Jiggz]

It is very possible the incorrect wiring of the kill switch could have damaged the cd-coil modules since it was providing a path to ground although it was indirectly through the choke coil. And probably so is when you use the choke and the kill switch is not reset or the pin or lanyard is pulled (meaning it is in closed circuit state) it can provide stray 12V power to the CD modules shunt wires (brown wires).

Now had the kill switch always been in reset mode, meaning the pin is in place and is in open circuit state, even with the choke being activated no stray power will connect to the cd modules. And this is probably the reason it ran as it did for the longest time without damaging the cd modules. But when the kill switch was activated, either intentional or accidentally, and you use the choke system, that was the last act that finally killed the CD modules.

Now since I did not actually did the testing and troubleshooting, all of this is just my logical conclusion based on knowledge of the system and your postings.

 

[Jiggz]

If after replacing one of the CD-coil modules and you still do not get any spark on any of the plugs, I will re-investigate the stator again. The cranking DVA reading of 355 volts is just way too high unless you were reading it wrong or had the DVA set wrong. Typically, cranking DVA for the stator ranges from a low 180V+ ~ 250V+ p-p. Don't get me wrong you can actually get a reading of 300V+ but only when the engine is running at high speed.

 

[MBJJ2369]

I appreciate the help everyone has given me here. I sure beats taking it to the shop. I will post an update when I get the new coils.

 

[jerryjerry05]

If I give parts to someone.
What I normally do is have you drop some $ or food at the closest animal shelter.
So maybe 15$ to a shelter??
Or you can pay me $100 on paypal??
Your choice?

The tach is pre set for a 50hp or 2 cyl.
Just be careful as it's old and can break very easily.
Maybe a coat of clear polish around the edge?

 

[MBJJ2369]

I really appreciate it and will make a donation to a shelter tomorrow. Again thanks

 

[jerryjerry05]

Glad I can help.
Some of these old parts were probably gonna end up in the local landfill.
​So why not feed the critters!!

 

[MBJJ2369]

The boat finally fired up this, I worked on it all day yesterday and today. I replaced the coils and the stator yesterday and tried to fire it up and still had no spark. I pulled the flywheel back off and found the magnet stuck around the stator. I cleaned both the flywheel and stator and epoxied the two back together and let it set for about 18 hours. Put everything back together, gave everything the once over again, bumped the key and she fired right up.

I don't know if it was the flywheel magnet the whole time, too tired to put the old parts back on to find out. But on the bright side, if it was, I got some back up coils and stator in case I have trouble down the line. The new coils and stator run me about 220.

Thanks everyone for the help.

 

[Jiggz]

Congrats. I wonder if the loose magnets were the culprit all along? Anyways, I hope you saved the CD-coil modules or stator for spare just in case. Or at least test them first to find out if it's even working before keeping them. Thanks for posting the final solution making this thread helpful to others.

 

[MBJJ2369]

I want to add one thing I did. The coils for this model mount extremely close to the block and if you are not careful one of the wires might get pinched. To prevent this, I added a couple of 1/4 inch thick stainless steel spacers to the back of the coils and used bolts just long enough to compensate for the difference.