Are both of these coils front or square coils?
If you hold the leads of the ohmmeter firmly together, what reading do you get?
If those are square coils, they have two circuits, primary and secondary. Primary is post to pig tail, secondary 7-8k ohms. You should see 2 to 2.5 ohms ( or less) on the
primary for a 6v coil, and 3 to 3.5 for a 12v coil. Readings should be 7-8k for both on the secondary. What do you get?
Al this being said......these tests will only tell you if the coil is bad, not if it's good. And coil failures on a cold start are rare. So I'd suspect a problem in the
distributor. The most common reasons for no spark or a weak spark on the front distributor are below. Check each one carefully. Even if you find a problem, check all 10:
1. The insulator under the brass concave head screw & where the copper strip attaches. (it's fiber & will wear out; poke & prod w/ your meter leads to make sure it still
works) If you need to replace the insulator, you have two alternatives. Cut up an old set of points to replace the metal strip and go to the hardware store for a .250 x 3/8
square nylon anchor nut to replace the insulator. Or the wiser alternative: buy the strip, insulator and brass screw from Tim Ponn at nnalert Tractor for $12. ( 440-437-
5572 phone orders only)
2. The pigtail at the bottom of the coil not making contact w/ the concave head brass screw inside the distributor. (With the coil on, the pigtail must firmly contact the
brass screw. No contact = no spark) Check for continuity between the top of the coil and the pig tail; a 6 volt coil will be around 1-2 ohms & a 12 volt coil should be 2 to 3
ohms.
3. The copper strip is broken or grounded to the plate. (look very carefully for cracks & breaks) .
4. The distributor is not grounded to the block because of paint or grease acting as an insulator. Or the points plate is covered in oil.
5. The tab on the bottom of the coil not making contact w/ the brass button on the cap. (With the cap on, the tab must firmly contact the brass button. No contact = no spark.)
Check for continuity between the top of the coil and the tab; you should see about 7-8k ohms.
6. A grounding issue inside the distributor: Incorrect positioning of the spring clip on the plate causing the pigtail to ground. (the open part of the clip goes between 7 & 9
o'clock on the plate. That puts the straight part of the clip opposite of the timing screw at 3 o'clock) or the condenser wire is grounding to the plate or side of the
distributor.
7. Incorrect seating of the coil on the distributor due to a loose bail or no gasket.(the coil must not move at all; if it does, replace the gasket or bail. Or stick some
cardboard under the bail).
8. Water/moisture inside the cap due to gasket failure or the absence of a gasket. (the cap AND coil have gaskets)
9. Dirty/corroded/burned/incorrectly gapped or misaligned points. I use only Wells, Blue Streak or Echlin brand points (* *see below). If you are using quality points and
cannot get the gap to open to .015, chances are you need to replace the bushings. If the shaft has any sideways movement AT ALL, the bushings must be replaced. If the tractor
has been sitting unused for a few months, its highly likely that the points are glazed. Dress them with brown paper or card stock. Do NOT use a file or sandpaper. That
removes the thin metallic coating on the surface and reduces point life considerably. With the points closed, you should have continuity between them; high resistance means
they are glazed.
10. Burned rotor, cracked/carbon tracked cap. Brass dust in the cap is a sure sign of bushing wear.
75 Tips
