Wico x-h magneto

~First, if you have a wire hooked to the little mag shorting post sticking out the side of the mag [REMOVE THAT WIRE] until you are sure your mag is working properly as those shorting wires are not need for the mag to operate but can cause all kinds of problems if shorted to ground.

..... .To Diagnose The Mag..... .

~With the mag still on the tractor, rotate the engine in the running direction & listen for the mag to snap. If you don't hear that distinctive Wico mag snap you have probably found your problem. If you don't get a good solid snap as the engine is turned over your problem is probably either a broken impulse cup spring, the impulse cup nut has come loose, the impulse dogs are rusted or stuck, or the mag is too tight to the governor [try 2 base gaskets]. To find the problem the mag will have to come off the tractor. If you pull the mag, first mark it's position to the governor case for re-assembly reasons, then pull the cap & note the position of the spark rotor, again for re-assembly reasons.

~If the mag has a good snap, then check the point gap to be around .015", then install a paper clip or bare wire in one of the caps attachment holes & bend to within 1/8"-3/16" of the coil's center button, then turn the engine flywheel or mag impulse cup [if mag is off the tractor] in the running direction [both turn the same direction while on the tractor] & make sure you are getting a good bluish colored spark to jump that 1/8"-3/16" gap MULTIPLE TIMES IN A ROW. If you do, your mag is probably good & your problem is from the spark rotor to the spark plug.

~If you pass the above test look at the cap & spark rotor for a sign of carbon tracking, water lines, cracks & other signs of damage. If all ok there, re-install the cap & rotor & install the plug wires in the cap, then take an old [KNOWN GOOD] spark plug & open the plug gap to 3/16", lay on the engine block [mag in tractor] or hold against the mag's metal case [mag off the tractor], then turn the engine [or mag's impulse cup, mag off tractor] in the running direction & see if you again get a bluish spark to jump that 3/16" gap. If so, your mag is probably "good to go" & your problem is in the spark plugs or wires.

~MAKE SURE you are using solid metal core spark plug wires & NOT automotive TVRS carbon core wires. Carbon core wires on a mag equipped engine are sure to cause you a problem.

~If you still aren't getting a spark from that mag, MAKE SURE the points or the stud that exits the mag case aren't grounding out to the breaker plate or mag case. If the points are not permanently shorting out make sure the points are clean & not oxidized & that the condenser wire isn't shorted out to the case. The number one reason a mag quits working is oxidized points.

~If all ok per above you might have a problem with that rust you found in there...Remove the coil, just remove the wire connections & remove the screws from the coil core clips & the coil should pull right out [if the coil feels stuck just turn the mag internal rotor until it will allow the coil to pull right out]. Once the coil is out pull the 2 core wedges & slide the coil core out. At that time you can wire brush the iron core & use a small wire brush, a piece of Scotch Pad & old thin bladed screw driver to clean the rust from the coil cores mounting area. If you have an ohmmeter you can also test the coil for opens, shorts & incorrect internal resistance [E-Mail me for coil specs].

~To answer your question about the coil, most Wico X coil's, either from Deere or other ignition product vendors DON'T come with a new center iron core. If your core is not rust pitted & just a little rusty all you need to do is remove the rust with a wire brush or Scotch Pad. If you need a new coil [or any other mag parts you can order them directly from Roberts Carb Phone: (712) 262-5311.

~In most cases the cause of a Wico mag working one day & not the next ISN'T the coil or rust but a points problem or impulse assembly spring.

~Do some of the above tests & post back with questions & I will be glad to walk you through any repair or other tests you need to run..

~One thing you should probably do if you haven't already done so & that is to install new spark plugs. Fouled spark plugs are a leading cause of no starts on the old Deere 2-cylinder tractors & you can't always see the fouling.

~It helps to print this page out & take it out to the tractor with you to follow while working with that mag.

First though, your specific questions:

Any of the new coils I've gotten, HAVE NOT come with a new center iron core, I just use my old ones, cleaned n wire brushed. Be sure the outer hold downs are clean and tight which increses magnetic efficiency. The lil thin wire goes to case ground and the larger insulated one goes to the points.

I normally use a soft wire brush when de-rustign those magnetic components.

You might try places (price maybe better??) like Magneeders or Roberts Carb Repair or Brillman or many of the other numerous supply shops for new coils or points etc. They all sell what they call "Hot" coils which are advertised to be superior to the standards for those Wico Mags, and if they are indeed superior in their energy transfer and magnetic coupling efficiency, you may get a spark of a tad more energy, but the firign voltage is primarily a function of the gap distance and the medium in which they fire (fuel and compression) and they, therefore, wont fire at any higher voltage, maybe just a slight more amount of energy. If you also buy a high magnetic strength rotor and a hot coil, you get more benefit, but unless your rotor is totally weak of any decent magnetic force, I would just stay with it and a regular or hot coil (ONLY if needed, see below). Most of the mag shops can re magnetize your existign rotor.

MAG TROUBLESHOOTING:

1) The most likely cause of a weak spark in that mag is first, bad points. First, check their gap to insure its 0.015. Second, if they look good and smooth but just gray oxide coated (should be silver colored), clean/polish them (light abrasive so you dont destroy any more coatign than necessary) and try her again. DO NOT leave any residue on the points or case where it can get on the point surfaces, blow all out clean and wipe thigns down. HOWEVER, if they are burned or black or pitted, REPLACE THEM, cuz thats more likely the cause of your problem than a bad coil as you asked. Also, look at its spring and all wires and make sure of no shorts. An ohm meter or continuity checker on its terminal and the other lead to case ground MUST show an OEPN circuit when they are open (high cam lobes) and a dead (or near dead dependign on their condition, dead is what you want) short when closed (off hig cam lobes). If when closed theres no dead connection (from points terminal) to case or its several ohms, they are bad like carboned or burned or pitted or not closing all the way. To work, there has to be an OPEN circuit to ground from their terminal when open and a short when closed. If not, find out why from wires or their spring etc and fix it.

Just to be sure, inspect the plugs and clean and gap them or even try a fresh new set, cuz fouled plugs can cause a weak spark, and if so, replacement is a quick inexpensive first fix.

2) Condensors do, of course, go bad, however, I seldom replace them unless I know for sure they are indeed bad like shorted and they dont go bad all that often. To DC or an ohm meter, they should appear as an OPEN circuit (after briefly charging) and NOT be shorted or show DC continuity. If shorted, it kills the spark.

3) Another cause of a weak spark and now none at all, might be any kill switch wires. If it has the kill switch stud and nut out the side, they can get shorted out where they go through the case, or the wire to them from the points shorted out. Inspect that and even remove any wires to it (from points) or that connect to it on the mags outside and see if she sparks.

4) Caps and/or rotors can be a problem, thoroughly inspect it for oil residue or cracks or carbon paths.

5) Bad leaky wires can be a problem, use wire core, not automotive carbon suppressor types.

SPARK TESTING:

6) First, does the mag produce a loud distinct sharp snap as the engine is cranked over????? ?? Remove the plugs and rotate the engine and listen. That mag should snap loudly (wind and spring trip mechanism) every 180 degrees of crank rotation. If not, she will never fire at cranking speeds, although she could run if pull started. If she dont snap loudly or its very weak, you may have a broken or weak trip spring or the trip dogs on the rear coupler are stuck or corroded. If so, mag removal and cleaning and brushign and blowing out then lubricatign the trip dogs may cure the problem. They have to turn out to enage to wind the spring. Dont move the flywheel and replace tha mag back in the same position (NOT 180 different) if you remove it. If its 180 out, reversing the wires would make her run though.

Try n pull start her and if she starts and runs fine then, you probably have a weak or broken spring or the rear trip assemblyy isnt working at all.

7) Remove the plugs and have their wires attached and their sides up against the tractors frame and turn the old girl over. Each plug shouild produce a good visible blue spark when the mag snaps to fire them. IF NOT, see if its a cap and rotor problem by removing the cap n rotor and attaching a wire or paper clip etc against the mags metal side frame to within 1/8 inch or so to the side output button/terminal on the coils side. Then rotate the mag and it should spark a good blue spark from the wires end to the coils output button (across the 1/8 gap) each time she winds n snaps over. If so but NOT out the plugs, the cap or rotor could be bad per above OR the wires may be bad OR the plugs are bad. If she still dont fire there and she snaps loudly and the points are good and gapped and clean, proceed below.

8) Rusty or coroded rotors or any of those other magnetic cores or components can cause a weak spark along with a low magnetig strength rotor. With the mag off if you rotate the rear coupler CW facing it (CCW should make her catch n wind n trip) do you feel any magnetic couplingp or resistance places each 180???? You should be able to.

9) Finally, yes, a bad coil can cause her to fail to spark. First though, check for any wiring shorts or frayed insulation inside. There should be a wire from the coil to case ground and the other heavier wire from the coil to the points and the wire to the points CAN NOT be shorted out. Likweise, as above, any kill switch wires to the points CAN NOT be shorted out. The coils primary and secondary windings MUST HAVE continuity, the primary side to points very low and the secondary out the side button/terminal several thousand ohms. If either are open, shes bad. However, even if she passes that low voltage contnuity check, she can still be bad breaking down (high voltage insulation failures) at high voltage under temperature. I would only inspect the coil AFTER I know the wind n trip are good, the points are good and gapped, all wirign intact and no shorted wires or kill switches, the rotor is good and not all rusty, and the cap and rotor is good and not oily or carboned tracked or cracked.

SUMAMRY, it may just need new points if she snaps louidly, but if not, suspect the cap n rotor and plugs and wires and weak or rusty magnetism or condesnor before buyign a new coil.

If you have last months Green Magazine, I had published a very long detailed afrticle on mag troubleshooting or I can e mail you it if this dont fix her. Post back your findings and any more questions. Good Luck n God Bless.

John T Nordhoff in Indiana

Will P