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Ignition Coil Question

Posted by itzbinnice Long Island NY (My Page) on
Wed, Dec 5, 07 at 21:42

I suspect my ignition coil is bad on my Deere Rider mower with a 9 HP Kawasaki.When the cold weather set in it just won't start anymore, no spark whatsoever then causes the engine to flood. Took the coil off and cleaned it and the flywheel, re-installed and set the gap but still no spark.
I did leave the grounding wire off thus eliminating any possibility of faulty wiring form the ignition starting circuit.

I will be buying a new one this weekend from a Deere dealer (51.00) but have a question I'd like answered.

Using a continuity tester I get continuity betwen the two legs and also from either leg to the grounding terminal.
I get no continutiy from any leg or ground terminal to the end of the plug wire. The plug wire is ok because on this model you can unscrew it from the coil and I get continuity from both ends. I tried baking the coil at 200 for 1 hour still no continuity.

A mechanic told me ther should not be any continuity between the legs and end of plug wire, that only occurs when the magnetic field is generated when the engine cranks.
I don't beieve that statement is true since the Kawaski service manual indicates there should be 10.9 - 16.3 Ohms by using the Rx1k range on the meter. These are the specs for the secondary coil from one of the legs to the end of the plug wire.

If anybody has a good coil laying around could you please test it and see if there is any continuity from anywhere on the coil to the spark plug lead. I will bring my meter with me when I buy the new one to test, but I would like to know in advance of what to expect.


Follow-Up Postings:

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RE: Ignition Coil Question

Does this model have an igniter as well? I'm not sure that all the 9 HP Kaws do. It is a small rectangular component w/ 1 screw and 1 terminal that leads to the coil. If you have this, clean it up as well. These fail too. You basically do the coil/ ignition test as shown in the JD manual.


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RE: Ignition Coil Question

There is only 1 terminal on the coil utilized for the ground to shut the engine off.
There is a small rectangular component the manual refers to as a control unit, I tested that according to the manual and it is OK, the wire from it does not go to the coil.


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RE: Ignition Coil Question

I may have a coil from a 14HP to test, tho I'm unsure if they are compatible in ohms /testing. Where does the wire go to from your controller? I don't recall having a 9 HP lose spark- tho they are scarce here. I also don't have an RX/SX service manual, but do have on several of the bigger ones to compare specs. What model do you have?


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RE: Ignition Coil Question

@tomplum
The model is a 1995 SRX with a FC290V Kawasaki.
I don't know what that controller unit does, but I just went out and checked the wiring and the controller has 2 wires on it. One goes to the coil, the other goes to the ignition circuit. I always thought that if you remove the ground wire from the coil the engine will always run, however, by removing the wire you wouldn't be able to shut it off without grounding that coil wire.

Don't know if the Kawasaki uses a different method and the controller plays a part in getting spark. Maybe I am on the wrong trail in replacing the coil. I can see the controller will be difficult to replace since it's in a very awkward location.


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RE: Ignition Coil Question

The control module is probably cause of no ignition,the coils rarely are the fault on kawi's. The second wire goes to ground the module. The kawi part is not cheap but you also can find inexpensive aftermarket modules on line at places like M&D Mower and many others. All L&G engine coils use them, Briggs and Tecumseh incorporate them into the coil but many Japanese engines do not. Even in the early days of electronic Briggs coils, the modules were added on, wedged between one coil leg and windings as they were modifying points style coils. Eventually Briggs molded the casing to enclose the entire two pieces.

If you have another kawi 4 stroker in your arsenal you can borrow its module long enough to verify if the dead engine is due to the module. Just make sure the ground is also connected or that the module body is grounded to the engine when testing.


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RE: Ignition Coil Question

@nevada_walrus
Many thanks for the information.
What exactly does the control module do?
I don't have any other Kawi engines or parts around to test.

I looked up the part on the Deere site and it refers to it as a "Module,KHI Engine Trigger", price is 54.00, 3.00 more than the coil.

These John Deere mowers really suck for parts, they have a monopoly on them and I must drive 60 miles to the closest dealer. I'm nervous about buying an aftermarket part from such places as M&D mower since it may not be an exact part and I won't be able to return electric parts.

I'm thinking about taking the control module off and bringing both to the Deere dealer, maybe they can examine and tell me which one is at fault.
What would you do if in my shoes?

Thanks to all who have offered their advice.


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RE: Ignition Coil Question

What is does is replace the points and condensor in ignition systems. Just as points and condensor systems this module is much more potential of being the failure over the basic coil. Modern Briggs or Tecumseh coils don't fail often but the ones that do, if they were to be taken apart by the factory and examined I would bet this point replacing trigger which is built into them is what fails.

What should you do? That's a hard one to answer. I think in the past 10 years I've had to replace one coil [this is based on all kawis not just your model] and probably 12-15 modules. I could say just buy the module but if you have that one you'd be really P.O.'d with me. There is an ohm test but I have found it totally unreliable so at this point have forgotten what it is. I have removed good modules off of engines head for the junk pile and keep them in my tool box for testing in these cases. Does your dealers techs do this, haven't a clue. If you can call them and find out and they do, it might be a good idea to load up the JD and let them check it out. Otherwise your dealer could end up charging you for both components. Just depends on his integrity.


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RE: Ignition Coil Question

nevada_walrus
I would never get pissed at anyone offering advice and it didn't work out. It's my responsibility to interpret this advice and make a judgement call, whether right or wrong, it's better than no advice at all.

I'll bring the parts with me on Saturday and have the Deere dealer offer his opinion, but I'm 90% convinced I'll buy the control module rather than the ignition coil.
If they act as points and condenser more than likly it is the culprit.

These Kawasaki engines are well made but a real chore finding parts and information on them.
My sincerest thanks for offering your time & knowledge with my problem. I'll post what the outcome is over the weekend so others may learn from my experience.


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RE: Ignition Coil Question

For what its worth, the coil I have has 2 small terminals on it and both have continuity to the plug lead. NW is right on what he says regarding the proportions of igniters vs coils. In my area, there aren't many of the 9HP versions that I work on so I can't tell you there. I too carry have an igniter in my box for test purposes and I would guess the the JD dealer techs do as well. The common igniter has 1 terminal w/ a split in the harness leading up to it. Is that the same as yours? For years all the single cylander igniters I knew of were the same part #, but then they started to produce a different spec'd one for the walk behinds. Know anyone w/ a JD walk behind? As stated, it would be nice if you had this thing in the back of your pick-up, one of the techs could take and hook up a test to see what you've got there. good luck.


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RE: Ignition Coil Question

@tomplum
Thank you for your wisdom, my igniter does have a terminal
lead on it and does have a split in the harness leading to it. One goes to the ignition coil, the other goes to a plastic piece fastened to the body under the shift lever.

Don't have a pickup to transport the rider, nor do I know anybody with a JD,looks like it may be a roll of the dice on which part it will be.
I'm still leaning towards the igniter rather than the coil.
Only been to the dealer once before and they seem like nice folk, hopefully they can steer me right.


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RE: Ignition Coil Question

There are 2 basic style of ignitor modules plus whatever different spec'd versions a manufacture may use. One and two wire. 2 wire modules the second is to ground the module to complete the circuit and make it work. The one wire type self grounds when screwed to the block or control plate.

I have a thought you may want to check out. The split where the wire goes to the coil and to the shift lever. The wire to the shift lever is a part of the safety interlock system to prevent running or starting if controls and operator are not where they belong during start or run.

My suggestion right now is to re-connect everything but dis-connect the wire at the shift terminal. This will disable the saftey system just in case the fault is with this. It may also disable normal shut off so don't actually try to start unless you are prepared to shut it off other then with the key, just check for return of spark.

Keep in mind the safety system includes having someone in the seat. If your checks for igntion have been with no one in the seat you may have no problem with ignition but something else wrong. Some systems allow spark with no one in seat if all controls are in neutral and the parking brake is engaged but i don't know if JD works that way or not.


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RE: Ignition Coil Question

@nevada walrus
Thanks so much for your help, I followed your instructions but appears I made an error in my description of wiring.
I just went out and reinstalled the coiled and set gap.

I stated that the other wire leaving the igniter went to the shift lever, it does not, it goes to the ignition switch. The wires in question are white, I now see there are three white wires near the shifter area. Two are going to the ignition switch

I'll do my best to describe.
Two wires off the igniter harness, one going to coil, the other going to ignition switch. When that white wire reaches the ignition switch it piggy backs with another white wire entering the 5 prong plastic connector for the ignition switch. It appears that second piggy backed wire is going under the flywheel and I suspect has something to do with the charging system. I caanot separate the two for testing purposes to isolate the white wire from the igniter.

I disconnected the wire from the igniter connector and used the continuity tester to verify the wire going to the ignition switch was the correct wire, it was, it showed continuity. This Deere is a real bear to work on, difficult getting your hands in between the mower body and where the electrical components are located.

Just wanted to advise I always sat on the seat when testing for spark, the seat switch is ok, tested and functions as should. This unit is designed that the starter wont turn unless in neutral and blade disengaged. What shuts the engine off is when either in gear or blade engaged and you leave the seat the engine cuts off. By sitting on the seat and testing I believe that would eliminate the saftety switch as being the cause since I know the switch works.

Just one more thing, there is what looks like a small heat sink near the solenoid that has a three prong connector, one red wire (it's hot), one white, the last black. Originally I thought the white wire was the one going to the igniter but it's not, there is no continuity going from that wire to the white wire coming from the igniter. Don't have a clue what that one for.


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RE: Ignition Coil Question

Brief follow up. Can't believe my stupiity. Just realized there is a fast disconnect plug on the wire leaving the igniter to the ignition switch. I disconnected it and then tried again for spark. There was a very faint spark on the first few revolutions, then nothing after numerous tries.

Seems like I'll just have to gamble and buy a new igniter and hope it's that and not the coil.


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RE: Ignition Coil Question

Not sure what the heat sink is associated with, it may indeed be part of the charging system. In any case, neither the charging system or battery will ever have anything to do with the ignition system. If 12 volts are every wired to the ignition system it will be almost instantly destroyed. That's where a lot of folks get in trouble when the key switch goes bad and they buy what appears to be a matching replacement from an auto parts store and get one meant for automotive use. Cars switch's put 12 volts to the ignition, very few L&G applications do.


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RE: Ignition Coil Question

"Cars switch's put 12 volts to the ignition, very few L&G applications do."

It appears this Deere SRX75 is an exception. There is a red wire that is a constant hot lead going to the ignition switch. It is coming from that piece that looks like a heat sink. Upon further inspection that heat sink is not a heat sink, but rather is a plastic piece (shaped like heat sink) with a 3 wire connector. The red going to the ignition, the white going under the flywheel (possibly charging circuit), and the last is a black which I would imagine is the origin of the power source, didn't have time to check it out this morning, gotta run I'm late for work.


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RE: Ignition Coil Question

The charging coil is under the flywheel. The part in question is probably a voltage regulator maybe combined with rectifier to send DC to battery and AC to lighting system. It probably is designed to also disapate heat.

12 volts will go to the switch to activate the starter solenoid but the switch will not switch anything to the ignition coil terminal. The ignition coil termninal on the switch does nothing more then short the ignition when key is turned to off.


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RE: Ignition Coil Question

I'm just going to bring my igniter and coil to the Deere dealer tomorrow and hope he can offer some assistance as to which part to replace.
If he can't help I'll just buy the igniter and hope that was the problem. I'll post the outcome tomorrow evening.


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RE: Ignition Coil Question

Went to the Deere dealer today with my igniter and coil.
Unfortunately there were no mechanics working on the weekend that I could discusss with. The parts man was a nice fellow and let me test both the coil and igniter with new parts with an ohmeter. Both my parts and the new parts showed similar readings.

He also stated using an ohmeter on the igniter is not a true test, and he suggested I replace the igniter rather than the coil. I bought the igniter and a new plug.

Went home installed the coil with proper air gap, then installed the igniter and connected the new spark plug.
STILL NO SPARK, yesterday I tested the ignition switch according to the manual and it's operating properly.
I'm at my wits end with this machine, my last option is replace the coil but I'm hesitant on doing this based on my tests with the new coil. Thought about trying to get a used one on Ebay but with my luck I'll get a defective one so I still won't know the source of the problem.


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RE: Ignition Coil Question

You seem to be very concise in your methods- but I have to ask anyway as I am not familiar w/ the 9HP's ignition specifically. Is there any way for the ignition coil to be installed backwards?
You do seem to be covering your bases here. You had mentioned that removing the terminal that connects the igniter to the ignition switch resulted in a weak spark. I would try this: Unhook your Ign harness completely (at the terminal just discussed and to the igniter and to the coil. From what you describe the harness would be not connected anywhere- correct? You also say that it piggybacks along with the wire to the charge coil. So at this point- confirm that you don't have a ground or any power in this lead. Then repeat the test while cranking. If both results are negative, with what you have described, and you still have a magnet in the flywheel- there isn't much left but the coil.


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RE: Ignition Coil Question

Only 1 way for the coil to go on, if reversed the ground lead would not reach.
Also I remember the plug wire exited coil on left side, I made drawing before removing the coil. it's on correctly.

As far as a short caused by a grounded wire that's not the case. Here the test I performed. I left the harness connected to the ignition switch and remoeved the ground lead to the coil.with ignition off, I then put one probe of the ohm meter to ground, the other probe to the lead going to coil, I had continuity to ground. I then moved the key to run, no more continuity. Indiactes to me ignition switch is functioning properly.

Next I thought perhaps a wire was grounding out somewhere,
I disconnecet the ground wire coming from ignition switch to igniter, I then disconnected both the igniter and coil leads. Put one probe on ground, the other went to all 3 disconnected leads in the harness, none showed continuity so I can rule out a short in the wiring.

I have two options, I saw a runnung 9HP Kawasaki for a reasonable price, just about double what I would pay for a new coil, buy the engine, try it's coil on my engine and hope that's it. Also would have many spare parts that are quite expensive if bought separately. The other option is to buy the new coil and pray it works. I like the first option better. I'm in no hurry to fix it now, I did my final leaf cleanup this weekend and winterized all my equipment. The Deere rider would have made things a lot easier that's why I was rushing to fix it. I now have time on my side but sure as heck looks like coil to me.



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RE: Ignition Coil Question

The coil could ohm out OK, but still be bad. If the insulation in the windings has broken down, the spark can ground out internally and you will not get any to the plug. I have seen this on a couple of toyota coils on automobiles.


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RE: Ignition Coil Question

@fixit
Automobile coils are entirely different than lawn mower coils, they rely on the engine to generate electricity whereas the automotive coil relies solely on a power feed to boost the voltage. From all my reasearch it seems like rarely do these Kawasaki coils (4 cycle)fail. I read one gentleman with over 30 years in the repair business, has only replaced one Kawasaki coil in that period. Seems a bit low to me, but that's what was stated.


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RE: Ignition Coil Question

May be repeating but just want to make sure this thing is connected correctly.

If ignitor has two leads, one is intended to go direct to engine ground. It must be connected for ignitor to work.

If ignitor has only one lead, the ignitor must be bolted in place to make a direct ignitor to block ground to work.

These are not shorting grounds to kill ignition but ground to complete circuit. Thse ignition system must as with any elecetrical ciruit make a complete loop to work. Ignition unit [in this case it is a two part unit which must have both parts grounded to block], ignition send juice to plug, circuit continues from plug to block and from block to ingition unit.

Killing ground shorts out the internals of coil, not the same as circuit loop ground. You may want to to ohm check ignitor bracket to block and coil to block to make sure corrosion or rust has not compromised that ground which is needed for circuit loop.


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RE: Ignition Coil Question

The igniter has one lead, with two piggy backed wires, one to coil, the other with a quick disconnect with that wire going to key switch. There are two terminals on the key switch regarding ignition. One wire is from ground, the other to igniter. When key is in the off position, the ground goes to the igniter, with key in run or start, the ground to igniter is no longer there. When testing the new igniter, it was screwed onto clean surface of the block, the coil is also clean with no rust.

The coil was gapped to .012 according to the specifications in the Kawaski engine manual. I can only see two possibilities of the problem, I received a brand new defective igniter, or the coil is bad since the plug is brand new and I tried several I had lying around.
Was so desperate I tried the test again in the shed at night with the lights off, not even a hint of spark.

I figure if I disconnect the fast disconnect wire coming from the igniter to the ignition switch this would bypass the safety features present. The only switch that could be defective is the seat switch, that and only that will cut the engine off. The seat switch functions properly. The other two safety switches are hooked up to the starting system, if in gear or blade engaged, the starter will not turn. Wire harness shows no continuity to ground so that would rule a short out.
I'm just about ready to take a sledge hammer to this Deere. They say "Nothing runs like a Deere", well not this Deere, it's a bear to work on, even something simple as an oil change they make complicated.


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RE: Ignition Coil Question

You are thinking this through correctly. I still would urge you to test for power and ground in that disconnected harness while cranking if you haven't done so. This confirms that you are not picking anything up via that wire running to the charge coil (you stated you couldn't isolate this wire).
I feel for you. These RER's can be a real pain to get around.


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RE: Ignition Coil Question

I did in fact isolate it when I found the quick disconnect wire coming from the igniter and going to the ignition switch. By disconnecting that wire it removed the seat safety switch from the circuit, yet the igniter and coil were still grounded by their securing screws.

I don't know what you mean by testing for power in the disconnected harness. There is no power going to the harness, only power would be what the coil generated.
Did I misinterpret something?


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RE: Ignition Coil Question

I took from part of your post:

"I'll do my best to describe.
Two wires off the igniter harness, one going to coil, the other going to ignition switch. When that white wire reaches the ignition switch it piggy backs with another white wire entering the 5 prong plastic connector for the ignition switch. It appears that second piggy backed wire is going under the flywheel and I suspect has something to do with the charging system. I caanot separate the two for testing purposes to isolate the white wire from the igniter."

So I assumed that the wire from the charge coil ran as part of the ignition harness, tho not meaning to be connected, as something that could be a wild card in your search. Is it possible that the wire from the charge coil is connecting to your ignition harness and is feeding power into your ignition circuit. I may have mis-interpreted what you had written.


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RE: Ignition Coil Question

"Is it possible that the wire from the charge coil is connecting to your ignition harness and is feeding power into your ignition circuit. I may have mis-interpreted what you had written."

Not possible, once I uncouple the fast disconnect connection any wire going to key switch is removed.

A bit hard to describe without being able to show a drawing.


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RE: Ignition Coil Question

Follow up ---- mower fixed.
I mentioned that I was attempting to get another motor for it, that didn't work out so I ended buying a new coil from the John Deere dealer. Put it in and she started right up.

As many have posted the Kawasaki coils seldom go bad, mostly the igniters. But I was the exception to the rule.
That's OK, although expensive, the main thing the mower is running again, and hopefully with two new parts she stays running for years to come. I winterized her and she's ready for the spring.

I'm sure most folks here heard of Murphy's Law, I've lived it many times over. For Christmas we will be entertaining.
Today the stove decided to crap out at the most inoppertune time. I traced the problem to the igniter and was fortunate to get a replacement from a local Appliance Parts store, $65.00 later we're cooking again.

Merry Christmas To All


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RE: Ignition Coil Question

Great thread!

itzbinnice:

Oh well, you just played the mathematical odds and lost the bet. You did the best you could do without electronic test equipment. A DC ohm meter doesn't always tell the whole story.

Maybe an cheap old oscilloscope would have come in handy as you could have seen the pulse feeding the coil. As an afterthought, a shorted coil INPUT might fool a tech into thinking the electronic module is faulty. You would have to provide the output of the module with a dummy test load to prevent that from happening.

I would think most OPE techs have the luxury of shotgunning by swapping parts.

Anyway...Merry Christmas!


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RE: Ignition Coil Question

I have a J/Deere with a Kawasaki, and I was told by a lawn mower supply person that John Deere got the Japan to lock up the market for them, on the lawn mowers, also if the black wire falles off the Ignition switch, a full 12 volt will travel down and destroy the coil, I'll bet no one else has found this problem. They have made it to expencive to fix those lawn mowers. I remember when off brands sold for beteen $18.00 and $25.00. I guss it takes alot to keep the deere stock prices high in the financial invester market.


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