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Subject: Carburetor

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Theo Morris    Posted 07-12-2018 at 04:35:35 [URL] [DELETE]        [Reply] [Email]  
  • Carburetor
  • I joined this forum today. I need help diagnosing a problem with my carburetor. It will only stay running with the choke all the way out, not like black smoke coming out of the tail pipe. It runs smooth with the choke out. When I push the choke in, it will die or the governor will surge a little bit and die unless I pull the choke all the way back out again. I have a 1939 9N model which I just purchased a week ago. Any ideas?

    Theodore Morris    Posted 07-13-2018 at 13:10:20 [URL] [DELETE]        [Reply] [Email]  
  • Re: Carburetor
  • Thank you for all your help. I have found the problem. This tractor was painted gray and the carburetor was painted as well. I do not know how gray paint got inside but gray paint clogged the main jet port. I rebuilt the carburetor, running good and strong now. Now I am having a problem with the charging system. Iím not familiar with a 6 volt system. How much voltage should be coming out of the generator? It is a single post generator. Somebody removed the ballast resistor and I do not know how this is charging the battery. I have to disconnect the battery every time I run it or else the battery will go dead.

    Tim Daley(MI)    Posted 07-13-2018 at 17:07:07 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Carburetor
  • Excellent! Fuel issue resolved. Now moving on to the electrical. The generator cutout voltage is 7.0-8.5 Volts but it is the AMPS your looking for. Your setup may vary depending on what you have. You say you have a '39 9N. If it is and original, it would have the small 2-Wire/2-Brush 'B'-Circuit generator, a square VOLTAGE REGULATOR; and use the 6V POS/GRN system. Look behind your dash on the steering column, Do you see the VR or is there a round-can cutout? Is the generator a 1-Wire unit? The two early '39 gennys had a 7 AMP output. After s/n 12500 the 1-Wire/3-Brush genny used the round can cutout. The later 9N-10000-C genny now had output of 11.5 AMPS. You will need to verify s/n to start with, then verify which setup you have. Here is the wiring for the post s/n 12500 using 1-Wire/3-Brush genny and the round can cutout:




    Tim Daley(MI)

    dave #1    Posted 07-13-2018 at 04:42:21 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Carburetor
  • Good to have you aboard !
    It's been said that sometimes your running problems are not your carburetor but a weak ignition that needs more gas in order to run (Choke on)??

    Now I have had 2 cases where I had running problems on 2 different N's that were carburetor related , both cases I removed the carburetors, disassembled, cleaned with carburetor cleaner and high pressure air, all ports that I could see were open and clean, installed the carburetors and they didn't run any better, I ended up switching carburetors with a good running tractor and that fixed the problem, I bought 2 Taiwan build Carburetors and fixed both tractors .

    For what it's worth.


    K.LaRue-VA    Posted 07-13-2018 at 20:32:07 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Carburetor
  • I've rebuilt a bunch of the M/S originals, unbranded replacements, and a Zenith replacement. Most tuned and ran like a new carb. The plain case replacement carbs are always of inferior quality. All you have to do is look at the castings and how they were finished. The machine work is always poorly done. Most of them can still be rebuilt, and they will work just fine. One of the unbranded smooth case replacement carbs I rebuilt did not work. I took it apart and went thru it again, and that particular carb still would not run right. I could get it to idle fine, and run high RPM, but it would not transition from idle to main jet without stumbling, unless I advanced the throttle painfully slowly. Finally took it apart, salvaged everything for spare parts, and tossed the top and bottom castings in the trash.

    dave#1    Posted 07-14-2018 at 14:37:46 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Carburetor
  • I agree with the inferior quality and appearance "BUT" both Taiwan Carburetors are still working great (Which surprises me!!)One is 4-5 years old on my main working 8n that I mow and plow snow with. and the other was installed a couple of years ago on a friends 2n that he also mows and plows snow with?

    Who knows ??


    Tim Daley(MI)    Posted 07-12-2018 at 05:18:25 [URL] [DELETE]        [Reply] [Email]  
  • Re: Carburetor
  • Welcome aboard the NTC Theo! Your carb is probably due for a rebuild. Being a newbie, best to get the essential manuals. There are procedures in the manuals on rebuilding the carb distributor, generator, starter and other parts. We also have a ton of info in our HOW-TO's forum as well. In MANUALS you'll find scans of many of the originals so feel free to download whatever you fancy. The important facts to know about your tractor are: All 9N, 2N, and early 8N models have a front mounted distributor. The 9N and 2N have a 3-speed forward transmission, the 8N has a 4-speed,both with a reverse gear. The 9N and 2N models only had DRAFT CONTROL. It was designed and built into the hydraulic lift system. The 8N model introduced POSITION CONTROL as well and came with a selector handle on the RH side of the seat to use in either draft control mode or position control mode. ALL FORD vehicles were originally 6-VOLT/POSITIVE GROUND electrical systems. Nowadays it isn't unusual to find one that has been switched over to 12-volts. A 6-V system will use a 6V battery, a generator and a cutout or voltage regulator. The 12V switch over jobs will use a 12V battery, an alternator, and no genny, cutout, or voltage regulator. Some tractors will just have a 12V battery installed in place of the 6V and if wired correctly will work fine. I rebuild carbs, distributors, gennys, starters and more, I sent you an email. Get a copy of Bruce(VA)'s "75 Tips for N-Owners" and "WIRING PICTOGRAMS by JMOR" downloaded an saved -very important to have with the essential manuals:




    Tim Daley(MI)

    BlasterStumps    Posted 07-12-2018 at 04:37:26 [URL] [DELETE]        [Reply] [Email]  
  • Re: Carburetor
  • There are supposed to be up to 3 screens in the fuel system. One on top of the fuel shutoff inside the tank, one in the sediment bowl of the fuel shutoff, and one in the elbow going into the carb. I would make sure they are all clean and that you have good flow to the carb. There should be a plug on the bottom of the fuel bowl of the carb. If you remove that plug, it should run a steady stream. Also, if I am remembering correctly, the tank has a vent hole that can be plugged.

    K.LaRue-VA    Posted 07-12-2018 at 10:06:53 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Carburetor
  • Yep, if the tractor runs fine with the cap off, but begins to stall when the cap is on, the tank vent is plugged. The vent hole is under a small dome at the top of the tank. The vent really isn't accessible even if the tank is completely removed from the tractor. It might be possible to bend a wire and use a mirror to rod out that vent hole working thru the fill hole. Most of us just drill a tiny new vent hole in the fill cap.

    Tim Daley(MI)    Posted 07-13-2018 at 05:09:30 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Carburetor
  • Kebby-
    Yes, I always forget about the fuel tank vent. It should be added to the fuel flow test procedure. Though N systems cannot develop a vacuum lock, they can get vapor lock. The vent hole can be cleared if the tank is completely removed from the hood (the tank is fastened to the hood) however, as quick and simple a job as that is, the project is extremely time consuming as several components need t be removed before the hood can be pulled off, including draining the tank. This feature is one of the hiccups in the Ford N design. A plugged vent is often equated with the gas boiling in the tank once it gets hot. That debate is continuous. Vented gas caps are available -Ford Service Bulletin Gas Cap Exchange Program and new types at Red Rock Mfg. The odds of hitting the vent hole with a wire are about a million to one. I have reached in with my long extended air gun stem in hopes of clearing it, but it is a crap shoot as well. I also have drained my tank with a special fuel line attached to the bulb outlet port, then reached in with the air gun and blow out the inside. Again, a crap shoot to remove any debris. Then I've inserted a old wet vac I devised to suck out any loose gunk -it works but no way gets it all out.



    *NOTE: This program may no longer be valid. Check your local CNH dealer.

    Tim Daley(MI)

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