Yamaha 200 saltwater series no spark cylinder #4

Thomas Roatan

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Joined
Feb 12, 2015
Messages
4
Greetings Guys-

I'm the new guy and have a corker of a problem. After about 15 seconds of upper rpm running, #4 cylinder drops it's spark. I have verified that there is in fact nothing coming from the coil. This is a twin engine boat, so have swapped all ignition parts( stator, pulser, CDI) from the good running engine, including the coils and new plugs. Still have the same problem. What am I missing? Do any of the oil or temp senders affect only #4? Thank you in advance for any help you guys may offer.

Thomas Roatan
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
Welcome aboard Thomas :welcome: great to have you join us...

Reading your problem I have to ask, what triggers the ignition to fire from the CDI and the following ignition parts? The problem doesn't seem to be the parts you swapped, but the trigger of the parts you swapped... Something is firing that setup at the appropriate time. Once you locate that, I think you will find your problem too... JMHO!
 

Thomas Roatan

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Feb 12, 2015
Messages
4
Thank you very much for your reply, gm280. I think your logic is right on point. If I understand your reply correctly, the triggering device that makes the CDI release it's spark is what some call the timer, some call it the trigger, though I believe Yamaha calls it the pulser. In any case it's a set of movable coils under the stator that sends a low voltage signal to the CDI, telling it to release spark when the inner magnets of the flywheel pass by them. The pulser is movable because it also allows timing advance when moved. On this engine there are only 2 coils in the pulser, one for each of two cylinders, and the remaining two are triggered by the crankshaft position sensor. My understanding is that the CPS triggers cylinders 2 and 5, so I have to rule that out because my problem is with #4. The pulser checks out okay with a peak reading voltmeter, but I swapped a known working one in it's place anyway and the problem persists. That's what I can't figure out, what's taking out #4 only. This oil injected motor has various oil-related sensors and temp sensors that will cause the motor to enter it's rpm reduction "safe mode" when activated, but I am not aware of any of them that take out #4. So, I follow your line of thinking that whatever does or doesn't trigger that cylinder is failing, but what? I believe it has to be something external to the actual ignition components. It happens consistently after about 15 seconds of medium to high speed running, and continues then at any rpm. What a corker.

Thanks again, gm280!
 

gm280

Supreme Mariner
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Jun 26, 2011
Messages
14,585
Thomas, do you have a schematic diagram for your engine? That could point to the actual setup and help your investigation. Even better yet, buy the factory specific shop manual for your model engine and it should take you through a step by step checkout procedure as well. Don't buy an after market manual that tries (unsuccessfully) to cover all the engine models because it leaves so much out for your specific engine. Always great to have the original shop manual anyways for everything concerning your engine... And do get back to us with whatever you find as the cause or even more questions. That way others can see what actually caused your problem incase they have a similar issues...
 

Thomas Roatan

Recruit
Joined
Feb 12, 2015
Messages
4
Again, Commander, thank you very much for your good sense reply. That's good advice about the model specific manual. I do have an aftermarket manual with the wiring diagram, but as you say, it tries to cover so many models that it can't possibly be complete on any particular one. Maybe that's the next step, to get the proper manual. I've been a working marine mechanic for over 30 years and have a motto, not to ever let one of these little puppies whip me. It's not rocket science. I will get to the bottom of it and will post the solution when it shows itself. I'm a little worried that it will be something stupid....... I sure welcome any feedback from you guys. I have considerable experience in various marine related areas and would be happy to help another member if I can.

Thanks again-

Tom
 

Capt Ken

Commander
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Jul 30, 2002
Messages
2,269
Being you work on engines you have forgotten one important element. Model number and year?
 

Thomas Roatan

Recruit
Joined
Feb 12, 2015
Messages
4
Hi Cap't. Ken- Thank you for your response. yes, i suppose I should have started at the beginning. This is a 1999 Yamaha 200hp Saltwater Series outboard. The powerhead has been replaced, block only, so all the ignition and fuel components are the originals. Looks like I've found the problem. I "adjusted" the non-adjustable crankshaft position sensor to bring it closer to the flywheel and "bingo", all was well. I stated before that my understanding was that the CPS triggered spark on #2&#5 cylinders, so still don't quite get why this fixed a no fire problem with #4, but these ignition electronics are sneaky. I'm not going to argue with success. The owner is out fishing right now.
Thanks so much, Ken and gm280 for your helpful insights and suggestions! Have a great weekend.

Thomas
 
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