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Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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I have an ignition problem on a 98 Kawasaki ZXI 1100. The #3

Customer Question

I have an ignition problem on a 98 Kawasaki ZXI 1100. The #3 spark plug is fouling continuously in spite of a new coil. I believe the ignition module is the culprit, but I hate to continue throwing parts into this ski hoping to find the right one. Is there anything else that can cause one plug to misfire?
Submitted: 1 year ago.
Category: Boat
Customer: replied 1 year ago.
Is there a test for the ignition module? I have seen a Kawasaki ignition tester in the service manual, but I only have a digital multimeter.
Expert:  RSRBOB replied 1 year ago.

Hi and thank you for your question.

In an honest effort to help you get your bike fixed as quickly as possible, I respectfully ***** ***** you have an ignition problem and here is why. Cylinders 2 and 3 are on the exact same circuit and any problem that you have on cyl 3 would be duplicated on cylinder 2. If they are not doing the exact same thing, you don't have an ignition issue.

Think about the ignition system as a whole. You have 4 cylinders, but only 2 coils. That means cyls 1&4 always fire at the same time, and cyls 2&3 fire together 180 degrees later. Motorcycle ignition systems do not use a distributor type system where only one cylinder fires at a time.

The only components unique to each cylinder is the high tension spark plug lead and the spark plug cap. It is easy to test this theory, simply revers the #2 and #3 spark plug leads and caps and see what happens. It will not change the way the bike runs if everything is fine. If there is a problem in the wire or cap, the problem will follow the wire and cap.

Since you know it is fouling, the best thing you can do is a compression test. I suggest testing all 4 cylinders and paying particular attention to cyl 3. After you do the compression test, do a leak down test on cyl #3 also. Listen for escaping air. I suspect you are losing compression past the rings.

Go ahead and test that and let me know what you get.


Customer: replied 1 year ago.
Customer I don't think we hit the mark with that explanation. This is a 3 cylinder, Kawasaki ZXI 1100 and not a bike. I have 3 cylinders and 3 coils. There is one hot wire from the stator that goes into the ignition module and 3 hot wires coming out and leading to the 3 coils. I think it's entirely feasible that there is a problem that effects one circuit in the ignition module, but doesn't effect the other two. My question is, how do you test these circuits? Is there a voltage range to the primary side of the coils that I can check for?
Customer: replied 1 year ago.
I haven't said this, but do you understand that this is a JetSki and not a motorcycle? The website said you are a marine mechanic.
Expert:  RSRBOB replied 1 year ago.

DANG IT!!!!!!!!!!!!!!!! I do now. How embarrassing. I read it as a ZX1100, not ZXI. Now it makes sense why you say it was one coil. I am as familiar with Jet Skis as Motorcycles so we can do this!

Now we can alter the previous instructions a bit and apply them to your ski.

I would suggest comparing the resistance of the #2 coil and #3 coil to see if you can detect a difference. Same thing with the spark plug cap. The next thing I would do is compare the air gap each coil will jump. You can take an old spark plug and open the gap up to 6mm and see if both cylinders act the same. There is no point comparing #1 to any of this because you are only having the problem on the rear cylinder. For the sake of simplicity, we are assuming #1 and #2 are identical.

I will consult the service manual for you and see what they have to say about checking the ECM.


Customer: replied 1 year ago.
Now we are tracking. I had the control box rebuilt by JetSki Solution so it has all new wires, caps, and one new coil (that coils wasn't bad, but it was a cheap, after market unit). The only thing they said they could not do is test the ignition module. I have the factory service manual that has a test procedure for the ignition module, but it requires a Kawasaki tester that no one seems to have. I understand this Kawasaki tester is just an analog multimeter, and I only have a digital multimeter. I have put my spark tester on it and the spark on #3 has been intermittent, but that was before the control box was rebuilt. I'll try the spark tester again with the air gap open as you suggest and see what happens. With all I have done to it, is there anything other than the ignition module that can cause this misfire? My thought is to check the output voltage from the ignition module to the primary side of the coils but would have no idea what that voltage should be. Your thoughts?Thanks!
Expert:  RSRBOB replied 1 year ago.

You have done a lot of logical tests. If we have intermittent spark on one cylinder, in addition to confirming weak spark with the wide air gap, you can also test for peak reading volts out of the stator, comparing each cylinder pulser to the other 2. Essentially, we only have 3 components that can contribute to an intermittent spark. The coil, the Ignition Module, or the pulser. We can swap the coils with the wide air gap test to see if the problem follows the coil or stays on the same cylinder. That would confirm or eliminate the coil. After that, you would look for the consistent output on all 3 pulsers or see if you have intermittent output on one of them. If we are getting a good signal in to the Ignition module and have a good coil to handle the signal out of the Ignition module. it doesn't leave many options. Obviously the Ignition module becomes the likely suspect. The only other possibility that comes to mind would be high resistance to intermittent open in a wire, but a resistance test and wiggling the wires would flush that out.

Customer: replied 1 year ago.
I won't be able to check this out till the weekend, but I'll let you know what I find. Thanks!
Expert:  RSRBOB replied 1 year ago.

Super. I get a notice every time you post here so just whenever you get new information, put it here. Until then, do what you need to do. No response necessary.

Customer: replied 1 year ago.
Customer Good news is that I replaced the ignition module with a known good unit and the ski is running 100% better. All three plugs are firing strong and are clean when I pull them out of the engine. There is still the slightest hesitation and RPM drop occasionally at full throttle, but I'll try replacing the plugs tomorrow and see if that doesn't help. I also want to rule out the stator so I put a multimeter to it and this is what I found:
Red to Purple wire - 455 Ohms
Black to Yellow wire - 30 Ohms
Does that tell you anything about the condition of the stator? Is there anything else I should check?
Expert:  RSRBOB replied 1 year ago.

Congratulations on the major achievement. It sounds like you are almost there. If you are getting a slight hesitation at wide open throttle, you might try opening the high speed screws 1/4 turn and see if it helps. It could be a lean hesitation you are feeling.

As far as the stator specs, I will check @ work tomorrow and get back to you.