Fixing a Coil?
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I have heard of people baking the solid-state modules in the oven and making them work again. I have never tried it. They seem to have a lifespan and every one is different. I just had one randomly go bad. The mower ran, I removed the engine to change crank seals and when I put the engine back on, the coil was dead. Weird. The old point ignition coils seem to live longer, but the ones from the 50's and 60's are known to break apart externally from old age and eventually stop sparking. What mower are you working on that has a bad coil?
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395 Posts
None currently but I did had a DF commercial that had a bad one. I just stole one off a DF silver pro. It is just something that was on my mind.
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4,417 Posts
Ive had a good amount of coils go bad. I even had new coils that i put on not have spark and i know it was the coil. You can heat them/bake them but sometimes they work and sometimes they dont.
My experience also while some claim they have lasted for years after baking. Don't know what it is with LB CDI Units as this have been a long time problem with little if any improvement. I once decided to take one apart and find what I was sure was a bad diode, resister, or other small component. Gave up.
Walt Conner
Walt,
It was probably the silicon controlled rectifier (SCR) that went bad.
It either shorted or opened. Seems like those are the main thing to go bad.
It's the only componet on the circuit board that has two functions.
The primary and secondary coils usually never go out.
The old one would have to be removed from the circuit.
This could be done with out actually removing the SCR itself, but
I don't think a new would could be installed afterword.
There just would not be enough room, at least to attach it to the curcuit board.
I suppoed it could be wired remotely, but where phycially on the mower so it would not be torn up ?
If I were still at Gale, I could do it, but then after I did it, the CDI guts
would be placed in a new plastic tray and re poured with epoxy to water proof it.
Also you need to be SURE it was the SCR causing the problem before you went digging the epoxy out.
You would also need the correct SCR for it, the gate values (voltage) of them were selected at Gale,speciffically for the CDI.
Too high or too low a gate, the mower won't start.
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4,822 Posts
I once had a real bad drought and all my mowers sat in the shed all summer... at the end of the season when rain started falling again I brought them out one at a time to get one running to cut the lawn. NOT ONE of them had a working coil. Go figure that one out. I decided I would only replace a couple and wait till I actually needed the mowers again. No sense replacing 8 coils and letting them go bad again sitting out in the shed. Good thing too, as we had little rain last year and nothing this year.
Heat and cold are the enemies of electronic components.
Some one at Gale one time had the bright idea that the big outboards were stored around the Great lakes, so they froze some 3 cylinder CDI's.
The fall out rate was like 75%.
They stopped doing that test, they just dealt with warrenties.
All the CDI's were tested hot tho. Around 200*.
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4,822 Posts
Its usually just a problem with solid state coils. The points coils like in all my D engines are still working. I have a lot of spares but only need a couple new ones for restoration jobs.
I just aquired the D engines a couple years ago. I have half a dozen Commercial D engines right now.
I just aquired the D engines a couple years ago. I have half a dozen Commercial D engines right now.
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5,142 Posts
I hate those cdi units...junk imo. At least with points I can limp her home if I have to mess with them a little bit. With those cd packs you have to remove them and fiddle faddle around with heat and such...ughhhh.
For the longest time the only things I was salvaging on scrap LB's was the cdi and the shortblock.....both have their place in todays world.
For the longest time the only things I was salvaging on scrap LB's was the cdi and the shortblock.....both have their place in todays world.
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15,219 Posts
I fixed many coils. Either I bake them or I find any coil that will slide on the laminations of the old one. I've used briggs coils on Kohler laminations a few times
And I put a Kohler coil on a boat lamination once. If it fits most of the time it will work. If its loose I J-B weld it on.
And I put a Kohler coil on a boat lamination once. If it fits most of the time it will work. If its loose I J-B weld it on.
Toasted ignition modules/CDI/SCR etc. (that little doohickey epoxied into the coil's casing) are nothing new. Heat & vibration wipes them out, maybe humidity from sitting also, if moisture migrated its way into the coil casing.
Relating to the Suzuki 2 stroke (47P) powered Toros - these coils suffer the same fate. Heating the coils in ovens works sometimes but usually just prolongs the inevitible. I don't think Toro used an external ignition module on these particular (22030, 35, 40) mowers, I believe they went from points in the first year of production (1983), to a coil-integrated module (module is epoxied/wrapped directly onto the coil) in 1984 and after. However, Toro DID use external ignition modules early on their line of CCR 2000 "snow throwers" that used the same engine;
http://www.partstree.com/parts/?lc=...SN+6000001-6999999)&dn=3312_773-2_773009-0008
Echo also used an external ignition module on their 1st year (1988) 2 stroke Kioritz powered LM-212 mowers;
http://www.partstree.com/parts/?lc=echo&mn=M14V+A1Z0&dn=4366
Here's the aftermarket external ignition modules used by most;
-www.gardentractorpullingtips.com/images/nova.gif
-Rotary "Nova II" module; P/N 8786
-Stens "MegaFire II" module; P/N 440-465
-Oregon "Universal Ignition Module"; P/N 33-053 (or 147-020)
Im sure someone's rewired their integrated coil to use one of these external modules, but nobody has reported back with results yet. Seems a $15 part to save a $150 coil unit just makes a whole lot more sense.
I'd like to hear more about substituting in a low-buck Briggs or Tucum. coil by matching "laminations". Theres only two bolts holding the coil on with adjustment slots to set your gap - exactly which coils match the bolt pattern and magneto "arc" of the 47P ? or Duraforce, for that matter ? ..or are you saying replace just the module on top of the original coil ?
Relating to the Suzuki 2 stroke (47P) powered Toros - these coils suffer the same fate. Heating the coils in ovens works sometimes but usually just prolongs the inevitible. I don't think Toro used an external ignition module on these particular (22030, 35, 40) mowers, I believe they went from points in the first year of production (1983), to a coil-integrated module (module is epoxied/wrapped directly onto the coil) in 1984 and after. However, Toro DID use external ignition modules early on their line of CCR 2000 "snow throwers" that used the same engine;
http://www.partstree.com/parts/?lc=...SN+6000001-6999999)&dn=3312_773-2_773009-0008
Echo also used an external ignition module on their 1st year (1988) 2 stroke Kioritz powered LM-212 mowers;
http://www.partstree.com/parts/?lc=echo&mn=M14V+A1Z0&dn=4366
Here's the aftermarket external ignition modules used by most;
-www.gardentractorpullingtips.com/images/nova.gif
-Rotary "Nova II" module; P/N 8786
-Stens "MegaFire II" module; P/N 440-465
-Oregon "Universal Ignition Module"; P/N 33-053 (or 147-020)
Im sure someone's rewired their integrated coil to use one of these external modules, but nobody has reported back with results yet. Seems a $15 part to save a $150 coil unit just makes a whole lot more sense.
I'd like to hear more about substituting in a low-buck Briggs or Tucum. coil by matching "laminations". Theres only two bolts holding the coil on with adjustment slots to set your gap - exactly which coils match the bolt pattern and magneto "arc" of the 47P ? or Duraforce, for that matter ? ..or are you saying replace just the module on top of the original coil ?
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395 Posts
Do you have any pictures of what you are doing. I just dont quite understand.
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15,219 Posts
Here is a good example...
This coil is for sale without the laminations .
Whatever you can get it to slide on will work.
It does not need to be a kohler.
http://www.ebay.com/itm/NEW-OEM-KOH...762?pt=LH_DefaultDomain_0&hash=item35b759beca
another...
http://www.ebay.com/itm/Kohler-Coil...263?pt=LH_DefaultDomain_0&hash=item5890f96bff
Here ia a lamination with out a coil. So any coil you can get to slide on the lamination with out it overlaping into the flywheel or hitting the block will work.
http://www.ebay.com/itm/genuine-Hom...226?pt=LH_DefaultDomain_0&hash=item19cb152212
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