8n no sparky (6V)

Rob (Wyo)

New User
Was running fine, all of a sudden no spark. Did some trouble shooting and found something that I have a question about. I am getting continuity between the wire from the coil going into the distributor, and the distributor body. Doesn't seem right but wanted to check with anyone who might know a little more about it. I get cont with the points closed and switch off, I get cont with points open or closed with switch on. One probe on the wire outside of the dist, one probe on the outside of the dist housing.
 
Good troubleshooting.

You found a direct short to ground.

Now to find out why.

You might just as well buy a new set of points & a condenser because you will be pulling the distributor to find the short.

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 & where the copper strip attaches. (it’s fiber & will wear out; poke & prod w/ your meter leads to make sure it still works)

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.

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....)

You can change points everyday & it will not fix bad bushings. If you are having trouble w/ points failure, check the shaft. If you detect movement, chances are it needs new bushings.

Inspect the points; if they are pitted or burned, replace them. 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. Make sure the points align correctly. Proper alignment is also critical to longevity. Look at the points when they are closed; both sides should mate evenly. Then, check the gap at .015 on the high point of all 4 cam 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.
50 Tips
 
(quoted from post at 19:57:33 09/28/12) Was running fine, all of a sudden no spark. Did some trouble shooting and found something that I have a question about. I am getting continuity between the wire from the coil going into the distributor, and the distributor body. Doesn't seem right but wanted to check with anyone who might know a little more about it. I get cont with the points closed and switch off, I get cont with points open or closed with switch on. One probe on the wire outside of the dist, one probe on the outside of the dist housing.
f you have a wire from coil to distributor, then you must have a later side mount distributor. I am always questioning when folks say they have continuity, so.........if you measure voltage to ground from that wire, while ign on & cranking engine, what does voltmeter show? Or even better if you connect a test light to that wire, does it light, blink, or stay dark?
 
" then you must have a later side mount distributor"

Ahhh ha!

There I go.........guessing again.

I'm thinking you got this one right.
 
So, did I guess wrong?

Front or side distributor?

If it's a side distributor & you follow my suggestion about removing the distributor......you will have another set of problems!
 
(quoted from post at 20:47:46 09/28/12) So, did I guess wrong?

Front or side distributor?

If it's a side distributor & you follow my suggestion about removing the distributor......you will have another set of problems!
appens to all of us, sooner or later or both sooner & later. :)
 
Yes, it is the later model side mount distributor with the round coil. I couldnt get it started so I put in new plugs (still wouldnt start) and cleaned up the points. After that it started. Then I moved it out of the shop and parked it outside and tried to re-start it and no go. Been setting for a week now. I have a sneaking suspicion that there is an insulator where the coil wire goes into the bottom of the distributor that is broken/rotted/gone....would this be causing what I am seeing? Thanks a lot for the quick replies! I may not get back to work on it till Monday but I will post what I find if anything. Thanks!
 
(quoted from post at 23:47:09 09/28/12) Yes, it is the later model side mount distributor with the round coil. I couldnt get it started so I put in new plugs (still wouldnt start) and cleaned up the points. After that it started. Then I moved it out of the shop and parked it outside and tried to re-start it and no go. Been setting for a week now. I have a sneaking suspicion that there is an insulator where the coil wire goes into the bottom of the distributor that is broken/rotted/gone....would this be causing what I am seeing? Thanks a lot for the quick replies! I may not get back to work on it till Monday but I will post what I find if anything. Thanks!
hat is one possibility, but so far, I'm not sure "what I am seeing" actually is? That is why I asked about light light, dark, blinking?
 
"I have a sneaking suspicion that there is an insulator where the coil wire goes into the bottom of the distributor that is broken/rotted/gone....would this be causing what I am seeing?"

That's entirely possible.

I'll guess (again) that you don't have the manuals, right? (see tip # 39)

Do you have battery voltage across the points when they are open? Verify the gap on the points at .025. Then, 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. (I always spray my feeler guage blade off w/ contact cleaner.) Make sure you have voltage across the points, as in past the insulator on the side of the distributor. That is a very common failure point on sidemounts, along w/ the attached copper strip. It's hard to find a short there because it is usually an intermittent. So 'wiggle' the insulator & the copper strip a bit when you are doing your checking. If you find the short there, the Master Parts catalog lists everything you need on page 154. You can make the strip and you could also make the insulators as well. But, somethings are just easier & in the long run cheaper to buy. Get the strip, 12209, screw 350032-S, 12233 bushing & 12234 insulator & just replace it all. If you just replaced the rotor & lost spark, put the old one back in. Insure that the rotor fits firmly on the shaft & that the little clip is there. Make sure the distributor cap is not cracked & doesn't have carbon tracks. Check continuity on the secondary coil wire. Make sure it is firmly seated in both the cap & the coil. In fact, replace it temporarily w/ a plug wire. Next, remove the secondary coil wire from the center of the distributor cap, turn the key on & crank the engine while holding the end of the wire 1/4" from a rust & paint free spot on the engine. You should see & hear a nice blue/white spark. If not, you have a bad coil or condenser. Just put the old condenser back in to eliminate that as a possibility.

Post back w/ results; I'll be interested in what the problem was.
50 Tips
 
Well I took the distributor apart and the insulator and bushing are fine. 2.4 Ohms across coil, I am assuming it is okay? Not sure where to go from here, other than replacing the copper strip that I ripped in half trying to tighten the nut with a pair of pliers.......
 
Not sure where to go from here, other than replacing the copper strip that I ripped in half trying to tighten the nut with a pair of pliers

Rob, I don't mean to sound rude here, but you need to use the right tool for the job, not pliers.
Replace the strip, it won't work without it and it could have been the place for your ground.
You can make one from the copper strip off an old point set if you have one.
As a tip, you can't measure continuity with power applied. At best it will give you a
false reading, at worst ruin your meter.
Bruce and JMOR have both given you things to check once you get the strip replaced.
Let us know what you find!
 
Sure, but when you live 30 miles from town and dont have a wrench that small, you use what you have. Just like if you don't happen to own a 3" wrench, a pipe wrench has to suffice. I measured the continuity to the coil with the power off, I read that it was supposed to be 2.4 ohms for 6 volt. I am trying like hell to figure out what the problem is and not just replace a crapload of parts, but I am about over it. I need this thing to run very soon and I work very long hours so no time to play with it. Thanks for all the tips, will read through them again and see if there is something there I have missed.
 
Just an update. When I found out how cheap the igniton part kit was I bought it just because. I installed points and gapped to .025, condenser, rotor, cap, and repaired the copper conductor that I broke. The old girl fired right up. Thanks all for the advice.
 

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