N Board Forum - Expanded Thread Page

Subject: no spark at plugs

[Back] [Return to Top of Forum]

James Terpay    Posted 05-17-2020 at 07:54:09 [URL] [DELETE]        [Reply] [Email]  
  • no spark at plugs
  • 2N Replaced wiring, cutout, and starter switch. New points rotor and cap. Coil and condenser not replaced. There is power to the coil but no spark at the plugs.

    James Terpay    Posted 05-18-2020 at 12:49:44 [URL] [DELETE]        [Reply] [Email]  
  • Re: no spark at plugs
  • Checked everything as suggested and did not find any major problems. The new cap just didn't seem right fit wise. Left the new points and old condenser in but put the old rotor and cap back on; nice spark at the spark plug!! Before I put the hood back on I'm going to get quality points, condenser, rotor and cap from NAPA. Thanks Bruce and Tim.
    By the way it is a OEM/6V pos. grnd.

    Tim Daley(MI)    Posted 05-18-2020 at 14:50:11 [URL] [DELETE]        [Reply] [No Email]  
  • Re: no spark at plugs
  • If the rotor doesn't seat all the way down, I've had some, it may not allow the cap to seat all the way down. In the gasket kit There is a round cork gasket around the cap that needs to be installed first. I once had to buy an aftermarket Cheena distributor (it was a Sunday, only thing open)at that 'tractor parts' store franchise next to McDonalds in town. I couldn't get the cap to seat down and discovered the rotor shaft sat too high on the unit. Be sure to press the rotor down all the way too. NAPA sells all quality parts, Made in the USA. Last June Farmer Dan and I spent a week going thru a dozen front mount distributors, rebuilding, and testing them. What we discovered was that the ECHIN Brand of pints, NAPA p/n CS-35, are no longer one of the better quality sets sold. The ones we tested could not be aligned, gapped, and timed correctly. There are three quality brands sold of the ones we tested. The good points are: Standard Ignition (Blue Streak); CNH; and TISCO. SI and CNH use the OEM type phenolic rubbing block/arm and the TISCO brand uses the plastic style arm. Two aftermarket tested were junk with similar results as the ECHLIN. The TISCO point kit includes a rotor, condenser, lube grease, and a reusable steel 0.015" feeler gage to set the breaker points with. My last set of TISCO lasted over 6 years. Here is my parts list:

    1. POINTS:
    ALT: CASE/NEW HOLLAND #87744524 or TISCO #ATK6FF. If NAPA doesn't have the SI part, don't let them sell you the ECHLIN brand. You can get SI on ebay too. $16 nominal on all 3.

    2. CAP: ECHLIN - #FA350 or STANDARD IGNITION - #FD-126



    5. GASKET KIT: SPAREX #S.60308

    6. 6V COIL: IC670




    10. CAM LUBE: SI #SL-2 or ECHLIN ML1

    Tim Daley(MI)

    Tim Daley(MI)    Posted 05-17-2020 at 10:14:23 [URL] [DELETE]        [Reply] [No Email]  
  • Re: no spark at plugs
  • How are you testing for spark? Save the info Bruce gave you for reference and get a copy of his 75 Tips. See the posit below yours and save a copy of that as well. You don't say but are you using the OEM 6V/POS GRN electrical system or are you attempting a 12V switch out job? Did you set the points correctly and set the timing correctly per the manuals? By 'starter switch' do you mean the pushbutton neutral safety starter button on the shifter cover? How did you determine it was bad as well as the roundcan cutout? Did you test the cutout per the I&T Manual? From our HOW-TO's has "WIRING PICTOGRAMS by JMOR". Download a copy for yourself as well. JMOR has done a great job showing every correct way to wire these old N's whether 6V or 12V. Doubtful if coil or condenser are bad, Coil can be tested static on VOM set to OHMS. Do you have the ballast resistor? The cutout is only used on the OEM 6V/system -if 12V it gets removed. Got the ESSENTIAL MANUALS? If not best to have them and read often.




    *NOTE: Cutout is only used on the 6V/POS GRN Setup with the generator.


    Tim Daley(M)

    Bruce (VA)    Posted 05-17-2020 at 07:59:25 [URL] [DELETE]        [Reply] [Email]  
  • Re: no spark at plugs
  • The first thing you need to check is for battery voltage at the coil. Yes, you need a meter for that, not a light. With the key on, you should see battery voltage battery with the points open and about half that with the points closed. If you do not see either, the problem is between the battery and the coil, e.g., the resistor, ignition switch or a bad connection.

    Assuming that the bushings & advance weights are ok (*see below), & that you have correct voltage to the coil , 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, 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) Check for continuity between the top of the coil and the pig tail; a 6 volt coil will be around 1 ohm & 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 6k 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. (*** see below) If the tractor has been sitting unused for a few months, it’s 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.

    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. The tracks should not be wallowed out.

    ** NAPA part numbers:

    . Points: FD-6769X or ECH CS35

    . Condenser: FD-71 or ECH FA200

    . Rotor: FD-104 or ECH FA 300

    . Cap: FD-126 or ECH FA 350

    ** Yesterday's Tractor kit:

    Premium Blue Streak points (A0NN12107ABS), rotor, condenser, and gauge Part
    No: APN12000ABSR

    ** Just8N's kit:

    Heavy-Duty Point Set, Condenser, Heavy-Duty Rotor, Heat Range Matched Spark Plugs. Packed 6 to Master Carton. Contains: 1-9N12107 Point Set, 1-AONN12300A Condenser, 1-9N12200 Rotor,1-9N12104 Gasket Kit,4-AL437 Spark
    Plug,1-015 Gauge, 1-025 Gauge.

    ** Distributor cam lube NAPA:


    *** There are three ways to replace the bushings in a front distributor:

    1. Buy new bushings (part numbers 9N12120 front & 18-12132 rear). Press out the old ones, press in the new ones and ream to fit. CAUTION: do not try this unless you have a press & know how to use it. If you break the base, a new one costs $130. If you bend the tower which holds the front bushing, a new plate will cost you $30. Resist the temptation to buy a new plate; most are pot metal and the threads will wallow out about the third time you change the points.

    2. Take the new bushings and distributor to your local machine shop.

    3. Send the distributor out for bushing replacement if you do not have a local machine shop

    [Back] [Return to Top of Forum]