Mystery solved with my JD 425, “IGNITOR” ?

   / Mystery solved with my JD 425, “IGNITOR” ? #1  

sriddle1

Silver Member
Joined
Apr 2, 2014
Messages
212
Location
SW New Hampshire
Tractor
ACTIVE: JDX730 DAYS GONE BY: JD3010, JD790, JD425
Wanted to share this story for those who own a 425 workhorse. I followed the guidance of the blog and changed out the IGNIITOR and all is grand again. I do have a question for those mechanically inclined, what does an "IGNITOR" actually do, THANKS.

I’ve owned this '93 425 Garden Tractor since 2004, kept the maintenance up, never any problems, have a 47” front mount snowblower I run in the winter, during the summer I maintain 6 acres of grass. Started having overheating issues under any load, lots of oil consumption, I could hear a cylinder missing, engaging the mower deck would bring it to its knees, the plugs would foul with oil. I did all the recommended remedies, air filter, oil level, coolant, hydrostatic fluid levels, fuel filter, new plugs, new thermostat and then the local JD Dealership said, must be the head gaskets, BTW told them to change out the Vinyl Cam with Metal while in there so $$$ later and several PITA trips ($ 1K a pop) and still no fix. After all was said and done and lots of $$$$ the prognosis, the fouling plugs were due to its old age and needed new rings or perhaps the cylinder walls were worn. Why-I-Ought-Ta !

I started researching blogs out there and then discovered this out there “I have a 425 20hp Kawasaki twin cylinder. Engine runs perfect for about 20 min. then will instantly start to spit, sputter, & puff black smoke. If I shut off deck & idler back it usually recovers. Start mowing again, then it will continue to happen on & off. It might run fine for 5min. or 20min. but continues to act up. Seems to set it off by going on an incline. Action so far, rebuilt carb & adjusted float. Tried to duplicate by removing one plug wire but it doesn’t act the same.”

A response came in, I’m including this for those (unlike me) that are mechanically inclined to show the extensive testing performed. “I recently worked on a john deere 425 tractor with the same exact problem as you're having. It would start and run great for about 20 min. and then begin to cut out, skip, and lose power. Some of the things I did before I started looking at the electrical end of things were to drain out the stale gas that was in the tank and replace it with fresh stuff, made sure the fuel pump was running and pumping sufficient amounts of gas out the gas supply hose at the filter, and made sure that the gas tank cap vent was not plugged and allowing a vacuum to be drawn on the tank. I did this by loosening the tank cap when the engine started to act up, which made no difference in the way it ran. The air filter was clean, carb throat looked very clean, and I could feel the carb shut off solenoid valve clicking on and off with the key switch.

I finally began to suspect an electrical problem and began to check the wiring for any chaffing or rubbing which would cause a short, found none. I then went through the ignition system components and checked the resistance on the ign. coils, pulsers, and high-tension leads. All checked out to be within spec. I went to my local NAPA store and bought two in-line spark testers, sure enough, the left spark plug wasn't firing when it got up to operating temp. Using my digital multimeter, I back probed the L. side pulser wires at the ign. module harness while the tractor was running, (with my meter set on the AC scale) and found it to be putting out a good signal to the ignition module to fire the coil, I even checked the other pulser coil and found it to have the same output AC signal as the left side was. I could then eliminate the left pulser coil as the culprit. The next thing I did was to switch the ign. coils and high tension leads from one side to the other and found that the problem did not transfer, it was still on the left side, I could then rule out the coils and high tension leads since they both worked on the right-hand side. I also did the same thing with the spark plugs, no change. I knew that the left coil pos. terminal had battery voltage, but to be on the safe side, I installed a fused jumper wire from the pos. bat terminal at the starter to the pos spade connection at the L ign. coil, (disconnecting the harness wire there first), this made no change in the way it ran. I then could eliminate the time delay module because#1- it was feeding bat voltage to the ign. coils, and #2- it was energizing the ign. module to fire the coils, (albeit only the right side fully, and the left side when engine temp. wasn't up there too bad). I then checked the ign. coil wires to make sure that they were not grounded or shorted and found them to be in good shape.

So, by process of elimination, came to the conclusion that the ign. module, (john deere calls it an IGNITOR), was not firing the left side coil when the engine temp., (and therefore the module temp.), was hot. I plunked down 275.00 plus tax at my local deere dealer and bought the IGNITOR, PN: AM105574. Guess what- she runs like a new tractor now. Hope this helps."
 
   / Mystery solved with my JD 425, “IGNITOR” ? #2  
Think of it as a CDI box similar to what is on an ATV. It tells the engine when to fire at different rpm's
 
   / Mystery solved with my JD 425, “IGNITOR” ? #3  
Been there, done that. And the names used in different places led me down the wrong rabbit hole.
Told a friend (when he asked if I'd replaced the ignitor) that I did.. but it was the ignition module I'd changed. When he then stopped by to help, his first question was "I thought you said you changed the ignitor?". Duh, didn't even see it buried in there.
Changed it and fired up on both cylinders.. after everything else was already changed with new parts.
Good post to have in TBN archives.
 
   / Mystery solved with my JD 425, “IGNITOR” ?
  • Thread Starter
#4  
Thanks beenthere, Everything was going great until this morning, I bottomed out in a shallow ditch compressing the mower deck upward and after getting the 425 out the symptoms started again....DANG ! I'm going to have to look at how that module could have gotten hit, the wire connections kinked or something, all the symptoms are back ! I'm thinking the mounting area is not the greatest but wondering if I could mount somewhere else and lengthen the wires, or, would that hinder the electrical signals. I believe this module is sensitive to heat, I never have this issue in the winter so why have it that close to the engine, just thinking..........
 
   / Mystery solved with my JD 425, “IGNITOR” ? #5  
Sorry to hear that your again having issues with you machine. Not knowing anything about this tractor, your post made me ask this about the igniter:

I'm thinking the mounting area is not the greatest
Where is it located ? Can you post some photos of it's location?

Richard
 
   / Mystery solved with my JD 425, “IGNITOR” ? #6  
Post a pic of what the kinked connections look like. Not understanding how the ignitor can be hit by the deck.
 
   / Mystery solved with my JD 425, “IGNITOR” ?
  • Thread Starter
#7  
Sorry to hear that your again having issues with you machine. Not knowing anything about this tractor, your post made me ask this about the igniter:


Where is it located ? Can you post some photos of it's location?

Richard
Richard, go to the John Deere Parts Catalog under the 425 and look up PN: "AM105574", they have them in the GreenPartStore. The PIC they show is the mounted side you can see. Pull off your Left engine cover, the ignitor is mounted on the frame below the engine. I'm going to respond to beenthere, seems I have a new set of symptoms but that ignitor fixed the last set of symptoms, ran great !
 
   / Mystery solved with my JD 425, “IGNITOR” ?
  • Thread Starter
#8  
Post a pic of what the kinked connections look like. Not understanding how the ignitor can be hit by the deck.
Probably not the best post, it was conjecture that I "thought" it might have been hit or wires kinked. I agree with you, not way that occured, I wasn';t familiar with the structural set-up. It appears my symptoms are not the same, I let the tractor cool before sending this response, now I am besieged with a surging engine so I'm going to go through the usual candidates, air filter, gas cap, old fuel lines kinking at the connection to the gas tank and lastly carburetor. By the time I'm done with this all the connecting parts will have been changed. I found it really odd though, the ditch and immediately started this...... will be investigating. I was tempted to order another ignitor, but the surging is certainly different, I don't hear any missing cylinders whereas before the Ignitor change, that was certainly happening.
 
   / Mystery solved with my JD 425, “IGNITOR” ? #9  
I would start with the carburetor. Maybe the hit to the ditch upset the float or broke some debrie in the float bowl loose.
 
   / Mystery solved with my JD 425, “IGNITOR” ?
  • Thread Starter
#10  
Back to the 425 surging issue today......... Just went through checking the fuel line to the Gas Tank, no cracks. Pulled the fuel pump, small connecting hose solid no cracks + cleaned the electrical connections to the fuel pump. I don't have a pressure gauge to check the Fuel Pump Pressure, what other check can be made to ensure the fuel pump is working properly. I noticed the fuel filter with it transparent shell is not full when the tractor is running, just 1/2, is that normal, I would have thought it would be totally full. The Carburetor is beyond my skill set, I see rebuild kits out there.
 
 
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