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Subject: New generator stops working on 2n

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Steve Frysinger    Posted 08-06-2020 at 14:20:15 [URL] [DELETE]        [Reply] [Email]  
  • New generator stops working on 2n
  • For a few years I knew my genny wasn't working, but I was able to charge the battery up and be good to go for a few weeks at least. But last week my 2n died unexpectedly, and I determined that the (brand new) battery had been drained in a very short time. Charging the battery got the tractor running fine again, so I'm pretty sure it just didn't have enough juice to fire the ignition. I concluded that the cutout was probably the culprit for draining the battery, and I had just received a new genny, so I installed both (after bench motoring the new genny to make sure it worked). Once installed, I was able to determine that it was charging due to voltage changing from ~6.5 to ~7.5 volts as I brought the engine up from idle to full. (My ammeter doesn't work - need to replace that too.) So yesterday I did several hours of mowing with the tractor running great (and enjoying new plugs and wires). But in a back field (of course) it died and wouldn't restart. Topped off fuel just in case, but no soap. Since it had been hot and working hard, I thought that would be a good time to replace the coil (which I had on hand), but that didn't solve the problem. So I towed it to my shop and put a charger on it, after which it started right up. But when I checked voltages again, there's no voltage change with engine RPM, suggesting the new genny isn't working anymore. I'm thinking the (2 day old) cutout might have failed, and I have another available, but before I try that I wanted to see if there's something else the hive mind suggests that I check. BTW, the ignition switch SEEMS to be working properly, but I'm not sure how to test that for sure. And I HOPE a new genny wouldn't itself fail in a few hours of operation. Thoughts?

    Tim Daley(MI)    Posted 08-06-2020 at 15:29:34 [URL] [DELETE]        [Reply] [No Email]  
  • Re: New generator stops working on 2n
  • First thing I have to ask is does the generator have belt tensioning device? The unit mounting bolt does not qualify as a belt tensioner and hold secure. Is the generator correct: 1-Wire/3-Brush OEM type? You can have a local starter shop bench test gen & battery. Cutout circuit test is in the FO-4 Manual or shop can also do. Get wiring diagrams and verify via continuity. Disconnect any lights -you can reconnect after root cause solved. Don't guess. Problem solve. Get a working AMMETER. When tractor fails to run, check for spark right then. Is the OEM Ballast Resistor in the circuit? The coil can be tested static with an OHM METER. The Battery is the heart, life blood in any circuit. Simply charging the battery does not mean it is good and will sustain a full a charge under load. Some batteries can be junk out the door of the store. Start there and while he's bench testing battery, verify the wiring is exact as should be, no shortcuts. While engine is cold you can also do a fuel flow test, but I suspect your issues are electrical. Again, if generator (or alternator for that matter) isn't kept tight for the belt, it'll never charge.

    FORD TRACTOR 9N & 2N, AFTER S/N 12500, OEM 6V/POS GRN WIRING:



    FORD 9N-10505-B CUTOUT –USED AFTER S/N 12,500 TO S/N 258504 ON 9N & 2N MODELS ONLY:

    WIRING PICTOGRAMS by JMOR; OEM 9N & 2N ELECTRICAL SETUP:


    FORD N-SERIES TRACTOR FRONT MOUNT DISTRIBUTOR 6-v COIL STATIC TEST:

    FORD TRACTOR 9N-10505-B CUTOUT CIRCUIT TEST:


    FORD 9N-10000-C GENERATOR w/ BELT TENISIONING BRACKET:


    FORD N-SERIES TRACTOR FRONT MOUNT DISTRIBUTOR 9N-12250 BALLAST RESISTOR:


    FORD 9N/2N ESSENTIAL OWNER/OPERATOR/PARTS/SERVICE MANUALS:


    Tim Daley(MI)

    Steve Frysinger    Posted 08-06-2020 at 21:19:52 [URL] [DELETE]        [Reply] [Email]  
  • Re: New generator stops working on 2n
  • > First thing I have to ask is does the generator have belt tensioning device?

    It has the band system and the tension is fine. And the genny was working upon installation.

    > Is the generator correct: 1-Wire/3-Brush OEM type?

    Yes.

    > You can have a local starter shop bench test gen & battery.

    Battery shop tested that new battery was good, and I bench/motor tested the brand new genny. (I also tested the one I took out and verified it didn't work. Maybe someday I'll rebuild it, but....)

    > Cutout circuit test is in the FO-4 Manual or shop can also do. Get wiring diagrams and verify via continuity.

    Funny you say this. When I bought this tractor 35 years ago I bought an FO-4 manual. But about a week ago someone somewhere mentioned a 152 page FO-4, whereas mine has only 39 pages. I always wondered why folks were so psyched about this manual because I found it lacking. Once I learned I had the Reader's Digest condensed version I ordered the full sized one, and should get it soon. (No idea WHY they would call the small one by the same name...) Meanwhile, thanks for your attachments!

    > Get a working AMMETER.

    As I said, I will be installing one. But since modern replacements are really voltmeters set up to read current, I don't expect different results than my voltmeter shows. When I first put the genny in, I saw voltage changes (as I said) from ~6.5 to ~7.5 volts with changes in RPM. It no longer does that, so something has changed in the charging system. Hence my post.

    > When tractor fails to run, check for spark right then.

    I did that in the field. Plug light didn't light, but I could feel a minor jolt while holding the wire. That led me to try a new coil (I had been meaning to change that anyway). But I think it the poor spark was due to the low battery. Once I got it back to my shop and charged it up the spark tested fine.

    > Is the OEM Ballast Resistor in the circuit?

    Yes, though it's probably due for a change. 35 years ago, when I bought this tractor, it had a 12 volt battery in it negative grounded, and the owner didn't know why it wouldn't charge and he had to jump start it! I set it back up with 6v positive ground, and replaced the resistor then. So it's been awhile.

    > The coil can be tested static with an OHM METER.

    I'll try that on my old one, since the new one is in the tractor.

    > verify the wiring is exact as should be, no shortcuts.

    I have, and will double check. But since it's been running very reliably for me for 35 years I'm pretty sure it hasn't changed. But it might have grown some rust shorts and such.

    > While engine is cold you can also do a fuel flow test, but I suspect your issues are electrical.

    I agree. It runs fine when the battery's full, with no evidence of starvation.

    The reason I posted was for ideas about where else I might have a phantom drain on the battery besides the cutout. I know they are notorious for failing (even new ones) and can drain the battery. But are there other PARTICULAR places where folks have seen battery drains on these machines? Given the rains, I have about 5 days to sort this out, so I don't want to do a complete rewiring job right now if I can avoid it.

    So, besides the cutout, where else have y'all found battery drains on your machines?

    Thanks Tim!
    Steve

    steveVa    Posted 08-08-2020 at 12:18:00 [URL] [DELETE]        [Reply] [No Email]  
  • Re: New generator stops working on 2n
  • I would check and see if genny motors when tractor is sitting off. You would have to take loose the belt.

    Steve Frysinger    Posted 08-08-2020 at 16:16:54 [URL] [DELETE]        [Reply] [Email]  
  • Re: New generator stops working on 2n
  • I motor tested it before installation and it did fine. But when the tractor died in the field after a few hours of work, and I towed it back to my shop, I tried to motor it again and it wouldn't. Seems strange that a new genny would just up and fail in such a short time. I'm going to go over the wiring with a fine tooth comb, and will take the opportunity to replace the terminal block and resistor, as well as install a new ammeter. That in itself will clean up a lot of old connections that might be hiding a short. I guess I have to think about a new genny too.

    Tim Daley(MI)    Posted 08-07-2020 at 06:52:34 [URL] [DELETE]        [Reply] [No Email]  
  • Re: New generator stops working on 2n
  • You’ve done some good homework but still some unanswered questions abound and making some assumptions and guesses. You say “…it's probably due for a change…”; “…But it might have grown some rust shorts and such…”, “…besides the cutout, where else have y'all found battery drains..; “…I know they are notorious for failing (even new ones) and can drain the battery.” The latter is not true. Where are you getting that from? Yes, you need a current copy of the CLYMER I&T FO-4 Manual –see picture. Early revisions like the one we have in our MANUALS forum have little technical info as does the newer ones have. Next, regarding the AMMETER, you say: “…But since modern replacements are really voltmeters set up to read current, I don't expect different results than my voltmeter shows.” Hmm. Where did you get that from? FORD old wives’ tales/myths? AMPS and VOLTS are two different things. OHMS LAW. Current (I) is measured by AMPS. Volts (E); Resistance is measured in OHMS; Power (P) is measured in WATTS. The 9N/2N generator is rated at 11.5 AMPS, 75 WATTS, and cut-in voltage is 7V (min) and 8.5 V (max). Where are you trying to measure to? Shorts usually occur by cracked or loose wires or just plainly wired wrong. Did you disconnect the lights when tracing wiring? Have you done anything to the distributor? It could be getting a short in it. The coil pigtail connection often will make intermittent contact to the distributor. Take needle nose pliers and stretch it out so when it compresses on the unit it makes a good solid contact. The coil has a single wire. It connects to the LH Terminal Post on the Ballast Resistor as viewed from the back of dash. Once wiring is verified to be correct and power restored to battery (lights still disconnected), proceed with your VOM set to DC VOLTS. Set one probe (it doesn’t matter which one) to the LH Coil post on Resistor. Set the other probe to a spot of metal on the tractor ground. Turn Key Switch “ON” but do not turn over ignition. You should get a reading of battery voltage, 6 VDC with points open, half that with points closed. If no reading, problem may be in distributor. Cross that path later. Other possibilities can be checked too. See the single wire on the generator? Is it connected the cutout ARM (or GEN) terminal? Note the cutout BAT wire. Trace it. It should feed to the central terminal post on the Ballast Resistor. This terminal also feeds one side of the Ignition Switch, and then thru the AMMETER and from there to the Start Switch that connects to the Safety Starter Pushbutton on the shifter housing which is also connected to the NEG battery terminal post. Any of these are also possible.

    FYI:

    OHM’S LAW
    I = CURRENT (AMPS)
    R = RESISTANCE (OHMS)
    E = VOLTS (V)
    P = POWER (WATTS)

    E = I x R to find VOLTS
    I = E/R to find AMPS
    R = E/I to find OHMS
    P = I x E to find WATTS


    Tim Daley(MI)

    Steve Frysinger    Posted 08-07-2020 at 09:02:51 [URL] [DELETE]        [Reply] [Email]  
  • Re: New generator stops working on 2n
  • Tim, I’m sure you understand this better than you let on, and know that it’s simple to make an ammeter from a voltmeter by putting a known resistor in the main circuit. The advantage is that this is more robust than running the circuit through the gauge directly. The idea that manufacturers are doing this now came from these tractor forums, but they could just be blowhards trying to make themselves feel good.

    Tim Daley(MI)    Posted 08-09-2020 at 05:32:58 [URL] [DELETE]        [Reply] [No Email]  
  • Re: New generator stops working on 2n
  • Yeah, didn't want to get into all of that, but still need to know how you are measuring the generator with a VOM. Slapping an AMMETER on the dash and connecting two screw terminals takes about 15 minutes, right? How do you know the old one is bad, did you test it?

    Tim

    Steve Frysinger    Posted 08-09-2020 at 08:05:32 [URL] [DELETE]        [Reply] [Email]  
  • Re: New generator stops working on 2n
  • As I said in my original post, I observed voltage change as a function of RPM5663. Many folks prefer to have a voltmeter on the dash (and indeed that has become standard in modern vehicles). My ammeter hasn't budged in 35 years, so I feel comfortable replacing it... :)

    TheOldHokie    Posted 08-07-2020 at 16:09:31 [URL] [DELETE]        [Reply] [No Email]  
  • Re: New generator stops working on 2n
  • Using a "voltmeter" to measure voltage drop over a known shunt resistance is a common ammeter design. Accurate and no need to size the meter components for large current flows.

    TOH

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