9n no spark

[Rog-i]

This tractor is now on 12v. I have fire at the points, but nothing on the plugs. Does having fire at the points mean the coil is good or can only the junction that goes to the cap be bad? I dont see any cracks in the cap. Thanks

 

[Dell (WA)]

Rog......uhm? fire at the points is a good thing. Look at the bottom of yer squarecan ignition coil. The coil springy-thingy makes fire at the points. the "tab" makes fire for the sparkies thru the rotor and 4-nipple cap. Sometimes you need to "bend/twist" the tab for more certain contact to feed the rotor.

Uh? You did re-install the rotor, didn't you??? ......Dell, yer self-appointed sparkie-meister

 

[Bruce (VA)]

Assuming that the bushings & advance weights are ok, & that you have voltage to the coil, the most common electrical failure (no spark, weak spark) points on the frontmount are:

1. The insulator under the concave head screw.

2. The insulator at the end of the points where the copper strip attaches.

3. The copper strip grounded to the plate.

4. The condenser wire grounding.

5. The pigtail/tab not making contact.

6. Incorrect positioning of the spring clip on the plate causing the pigtail to ground.

7. Incorrect seating of the coil on the distributor.

8. Water/moisture inside the cap due to gasket failure or the absence of a gasket.

9. Dirty/corroded/incorrectly gapped points

Unless the coil is cracked or shows a dead short, chances are it's fine; square coils rarely fail cold. Pull the distributor & do a continuity check.

First, make sure your meter/light works (don't ask....)

Next, dress the points by running a piece of card stock or brown paper bag through them. New points sometimes have an anti-corrosive dielectric coating on them & old points can corrode or pick up grease from a dirty feeler gauge or excessive cam lubricant. Then, check the gap at .015 on all 4 lobes.

Now, follow these steps:

1. Coil off, cap off, points open. One probe on the brass screw & the other on both sides of the open points. On the side closest to the cam, you should have continuity. Not on the other side! If you do, you will also have continuity everywhere because the points are grounded.

2. Coil off, cap off, points open. One probe on the brass screw & the other anywhere on the body of the distributor. You should have no continuity! Now, rotate the tang on the distributor....as the points open & close, you have continuity (closed) and lose it when they open.

3. Coil on, cap off, points open. One probe on the lead on the top of the coil, the other on the cam side of the open points. You should have continuity!

4. Coil on, cap off, points open. One probe on the lead on the top of the coil, the other anywhere on the body of the distributor. You should have no continuity!


At this point, I just put the distributor, coil & cap all back on the tractor as a unit (it’s easier to do this from the left side). The reason I do this is because it is real easy to get the cap or coil mis-aligned trying to put it back together one piece at a time & the result is something gets broken or you get a ‘no spark’ problem.

Post back w/ results & any other questions.
50 Tips