(quoted from post at 04:54:45 05/08/11) I 1939 9 n. front distributor, new plug wires, new ground wire strap, soft copper size one to starter, starter is good, starter switch is good and switch is good.
Did a total paint job this winter with new head, gasket and plugs to stop the age old overheating, loss of water problem.
Switch grounded out (behind the dash-replacement bolt was too long and touched the other bolt.
Melted coil, burned points. Replaced coil, replaced points (at 15 gap per spec) and replaced condenser. Everything clean in distributor and rotor and cap look okay.
Use an 8 V battery (with external charger) spins fine. I did jump 12 v to battery since jump to starter bolt had no spunk. (Because of the grounded switch I think).
Did I smoke the voltage regulator? All I have to test is a multi meter and I don"t know how to test electrical stuff!
I have no spark to plugs obviously. I have spark to top of coil, if I ground the wire, sometimes. Does not seem to matter if switch is on or off but I don"t recall. Not sure if I should have spark and when.
Distributor in on the work bench now. Should I bench test first?
Thanks
Gary
Is the tractor 6v or 12v?
I doubt you smoked a v/r because a 9N doesn't have one. Unless you have a non-OEM system.
Do you have a v/r or not?
"spark at the top of the coil" doesn't tell me jack. You have a multi-meter; use it! You should have battery voltage (see why I need to know that?) w/ the points open & about half that when they are closed.
Re the ignition switch, once again, use the multi-meter!
If it's OEM, it has two wires. One in, one out. Key on, battery voltage on BOTH wires. Key off, only on one wire.
As to bench testing the distributor....use the multi-meter!
As I just said, before you check anything else, make sure you have the correct voltage at the top of the coil. W/ the key on, it should be battery voltage w/ the points open & about half that w/ the points closed.
If you do not have the correct voltage at the coil, that’s your problem.
Assuming that the bushings & advance weights are ok, & that you have correct voltage to the coil, the most common electrical failure (no spark, weak spark) points on the frontmount are:
1. The insulator under the brass concave head screw.
2. The insulator at the end of the points where the copper strip attaches.
3. The copper strip is broken or 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 due to a loose bail or no gasket; the coil must not move at all.
8. Water/moisture inside the cap due to gasket failure or the absence of a gasket.
9. Dirty/corroded/incorrectly gapped points
10. Burned rotor, cracked/carbon tracked cap.
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. 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.
It's possible to put it back on wrong & break it. Look at the slot on the end of the cam shaft. What ever angle it happens to be, turn the distributor tang to match it. Make sure you can tell the wide side from the narrow side on both the cam & distributor! (close counts) Then place the distributor on the front of the engine, gently push it in place & slowly turn the distributor body until you feel the tang slip into the slot. Rotate the distributor body until the bolt holes line up. Then, hand tighten the two bolts until the distributor body is flush w/ the timing gear cover.
Finally, double check your firing order & plug wires. It’s 1-2-4-3, counterclockwise. It’s very easy to cross 3 & 4.
Post back w/ results & any other questions.
