8N Won't Start (No Spark After Coil Replacement/Tuneup)

winstarman

New User
48 8N 6 Volts.

Tractor started dying when warm and figured it was a bad coil. Picked up a new coil and tune up kit from local tractor store. After install of new parts tractor will not start and appears to have no spark (tested using the grounded plug trick). I AM getting 6v to the coil but I am unfamiliar with how to proceed with troubleshooting. I worked on it for several hours trying combinations of old and new parts and I can't get anything to work.

Thanks in advance!
Richard
 
(quoted from post at 05:49:38 10/07/14) 48 8N 6 Volts.

Tractor started dying when warm and figured it was a bad coil.

Not a good idea. Other things than a coil can cause a loss of spark when it's hot. Troubleshoot the problem BEFORE you start buying parts.

Picked up a new coil and tune up kit from local tractor store.

If that local tractor store was TSC, that's another bad idea. Get your N parts here or from nnalert's.


Assuming that the bushings & advance weights are ok (*see below), & that you have correct voltage to the coil (battery voltage with the points open and about half that with the points closed), the most common electrical failure (no spark, weak spark) points on the front mount are:

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, use a .250 x 3/8 nylon
square nylon anchor nut available at most big box home stores

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

3. The copper strip is broken or grounded to the plate. (look very carefully for cracks & breaks).

4. The condenser wire grounding to the plate or side of the distributor.

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.)

6. 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)

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).

10. Burned rotor, cracked/carbon tracked cap.

After find the problem & re-check the point gap, do a continuity check before you put the distributor back on the tractor. Before you start, make sure your meter/light works.
With the distributor still off the tractor, 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. Put the coil on the distributor, 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 misaligned 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. Whatever 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). 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. Hand tighten the two bolts until the distributor body is flush with the timing gear cover.

* Unscrew the plate hold down screw & remove the C clip to get the plate out. Remove the shaft & weights. The weights should freely move.

* *NAPA part numbers:

• Points: FD-6769X
• Condenser: FD-71
• Rotor: FD-104
• Cap: FD-126


75 Tips:

http://www.yesterdaystractors.com/articles/artint268.htm
 
Ok, so it's up and running again (running better than it ever has since I got it too.)

I think the main issue I had was the first few times I put the new coil on I must not have had the pigtail in good contact with the concave screw (or it was shorting against the retaining ring). After reading your response and thoroughly disassembling all of the top parts of the dizzy setup I installed everything again paying very close attention to A) not shorting anything and B) ensuring there were solid connections to the coil.

I found that retaining ring was in "upside down" so the opening was between the 9 and 11 mark so I swapped that just to be sure. The washers you discussed were all in good shape as well. I also had to bend the condenser fitting so it would not short out. I also attached the coil to the dizzy before completing installation of the insulating disc and rotor so that I could clearly see the pigtail make contact with the concave screw. Lastly, I carefully installed the new cap and reinstalled the whole unit onto the engine.

From that point it started great once I fixed the spark plug wires I had reversed on the left side of the cap. (oops.)

It's also worth mentioning that the service training manual also has a good write-up (and pictures) for servicing the dizzy.

So, long story short is that I now know how to install new points and the tractor is running a new cap, rotor, points and coil.

Thank you so much for taking the time to help a newbie out.
 
Borg Warner {BWD] also makes a good set of points
that lasted 3 years in my 9n. Part#A41 at Oreilly's
Auto,and they [here]stock other parts for Ns. Napa
in my town didn't have the parts and acted reluctant
to order any. lha
 
(quoted from post at 00:34:19 10/08/14) Borg Warner {BWD] also makes a good set of points
that lasted 3 years in my 9n. Part#A41 at Oreilly's
Auto,and they [here]stock other parts for Ns. Napa
in my town didn't have the parts and acted reluctant
to order any. lha

A few of the Napa dealers around me actually consolidated with one that's is a pretty good distance from me. They seem to have gone from a corporate business to a mom-and-pop shop.

I have a feeling that they are going to be a thing of the past. Hope I'm wrong.
 
"Borg Warner {BWD]"

FYI, there's NO connection between "Borg Warner" and BWD.

BWD = Standard Ignition/SMP.
 
(quoted from post at 03:56:07 10/08/14) "Borg Warner {BWD]"

FYI, there's NO connection between "Borg Warner" and BWD.

BWD = Standard Ignition/SMP.
Oh well,My bad! still good quality. I got a Neihoff cap from Ebay for about $15.00 shipped,old box,new cap. I remember getting Neihoff points and condensers for my old Ford and Dodge trucks a while back. Sorensen also made good stuff back then.
 
(quoted from post at 23:34:19 10/07/14) Borg Warner {BWD] also makes a good set of points
that lasted 3 years in my 9n. Part#A41 at Oreilly's
Auto,and they [here]stock other parts for Ns. Napa
in my town didn't have the parts and acted reluctant
to order any. lha

You brought up a good point for something I haven't seen in any of the tip listings...

How long should I expect a set of points to last? Are they pretty much a "replace annually" part if you don't want to be left dead in the field?

R-
 
(quoted from post at 02:40:34 10/08/14)
(quoted from post at 23:34:19 10/07/14) Borg Warner {BWD] also makes a good set of points
that lasted 3 years in my 9n. Part#A41 at Oreilly's
Auto,and they [here]stock other parts for Ns. Napa
in my town didn't have the parts and acted reluctant
to order any. lha

You brought up a good point for something I haven't seen in any of the tip listings...

How long should I expect a set of points to last? Are they pretty much a "replace annually" part if you don't want to be left dead in the field?

R-

I know I'll take some heat for this answer, but with a good gasketed distributor and the proper wiring setup...almost indefinitely....

While points are a normal maintenance item, like changing your oil, usually a good cleaning and a cam lube is all they need.
This is with old good quality points of course.
New stuff....who knows nowadays.
Points 'life' also depends on the condition of the distributor
they are in. Dust, rust, oil, bad bushings, all will shorten points life. And where you park it contributes too. Damp shed takes more points maintenance than just leaving them outside sometimes.

Funny about points. I use mostly used ones in old junk I buy from a box on my bench or just what's in there when I get it.
Clean and set old ones.....then forget it.
When I have to buy new....I know that tractor will take a lot more maintenance.....
Reading thousands of posts here about points, I really wish I could have all the points that have been 'taken out' and thrown away.
(tuning up tractors for other people who demand new parts is a gold mine for me!)
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top