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Subject: Need full choke to run

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Neal Pecha    Posted 08-01-2017 at 23:50:22 [URL] [DELETE]        [Reply] [Email]  
  • Need full choke to run
  • I was bush hogging my wife's pasture and the 2N was running great for about 3/4 of an hour and suddenly the tractor started to spit and sputter. I knew I only had a gallon+ of fuel, so I assumed I had run out of gas. After adding more fuel, it would only run smooth when I pulled the choke all the way out. (note, I never had to use any choke once it started previously) It did not have enough power to run the bush hog. I then ran the tractor back to my shop, but the motor galloped when in gear. Because it had run just fine before it started to spit and puttered, I'm wondering what I should check for. I have good spark and the engine will start with only a few reveloutions, but the choke must be almost all the way out for the motor to smoothen out. Any ideas appreciated.

    Bruce (VA)    Posted 08-02-2017 at 09:58:10 [URL] [DELETE]        [Reply] [Email]  
  • Re: Need full choke to run
  • Pulling out the choke gives you a richer mixture. So, you could have either a fuel or spark problem.

    A carb out of adjustment will also cause this problem; set the main jet at 1-1/2 turns out & leave it alone.

    A dirty carb can cause the problem as well; start by cleaning the fuel screens. (see tips 45 & 56)

    Dirty/old gas, or water in the gas can cause this problem.

    Restricted fuel flow can cause this problem; remove the bolt at the bottom of the carb & check for flow. The flow should fill a pint jar in under 2 minutes.

    On my 1950 frontmount, needing choke to run is the first sign that the points need adjusting/replacing.

    A vacuum leak can do the same thing. Get a hand propane torch and carefully spray it (unlit of course) around the intake manifold at the carb to manifold interface & the manifold to block gasket of the tractor while it is running. Or, you can use carb cleaner or WD40. If it speeds up, you found the leak. Sometimes (rarely) manifolds crack or get rust holes.

    Lastly, when all else fails, you could have an air leak around the carb metering section. The likely suspects are leaky throttle shaft seals and/or a worn throttle shaft. Or, just a real dirty carb w/ clogged passages.

    Bottom line: Probably 90% of "needs choke to run" problems are fuel related, but do not rule out ignition problems, contrary to what others may tell you. Iíve had that very same problem before w/ a rebuilt carb, fresh fuel & good flow & a tight manifold.......and it was a spark problem. But, that was unusual. Just check the likely fuel problems first.

    Please be sure to post back & let us know what the fix was. We all learn something if you tell us what worked!

    Neal    Posted 08-02-2017 at 14:56:35 [URL] [DELETE]        [Reply] [Email]  
  • Re: Need full choke to run
  • I removed the plug at the bottom of the carb and had a good steady flow. The spark looks good. It will start on 3 cylinders (one plug wire removed and attached to a test spark plug)and only needs a few revs to start. The puzzling thing is how it happened so abruptly with out any warning signs. Gas was fresh. No carb adjustments were made in the past. The gas tank looks clean inside. Tractor was always garage kept.

    Jack - Iowa    Posted 08-03-2017 at 07:58:33 [URL] [DELETE]        [Reply] [Email]  
  • Re: Need full choke to run
  • Neal,

    Bruce mentioned a vacuum leak. Since it occurred without any warning I would start there.Only takes a few minutes to check.

    Good Luck,


    carl nny    Posted 08-02-2017 at 15:29:01 [URL] [DELETE]        [Reply] [Email]  
  • Re: Need full choke to run
  • I'll start by saying that I'm not an expert.I had the same problem under the same circumstances last year and can only say what my problem was. With running it very low on gas I stirred up sediment in the bottom of the tank. I had to pull the tank and clean it and all three filters. After that it ran good again just like before. I learned that running the tank very low is a bad thing. I will now shut it off and walk back and get more gas before I open the shut-off valve more than two turns. Like I said in the beginning, JMHO.. That was "MY" problem but it could be all or any of the responses that the other guys have said also.

    carl nny

    Tim Daley(MI)    Posted 08-02-2017 at 09:28:26 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Need full choke to run
  • The Fuel Sediment Bulb is designed to run at nominal when the valve is open Two Full Turns as stamped on the valve knob. You open the valve all the way to access the last 1 gallon reserve. The fuel tank capacity is 10 gallons. The last 1 gallon is the 'reserve'. However, many try not to let it get that low as you could be sucking any debris in the tank at that point and possibly clogging the lines and screens. Once it starts sucking air too, you can create a slight vacuum and that may cause some sputtering as well. Running with choke fully open means a rich running mixture on carb so that could be a fuel or spark issue. Carb may be ready for a rebuild and/or some tweaking.

    Tim Daley(MI)

    Michael    Posted 08-02-2017 at 07:43:16 [URL] [DELETE]        [Reply] [Email]  
  • Re: Need full choke to run
  • I had the same problem just 2 weeks ago. On mine I have an inline fuel filter 4" above the carb, it was clogged. Oddly enough, I used the same remedy of pulling the choke. After I raized the line higher than the sediment bowl, the dirt drained back into the sediment bowl. I replaced the fuel filter and cleaned the sediment bowl. That solved my problem. I have also flushed the fuel tank again, just because time and resources allowed me to. That is the only fuel issue I have had since owning this tractor. I typically use my tractor for brush hogging my field and working on my pond when its dry. My land is all Oklahoma powdery red dirt that gets in eveything.


    Bruce(OR)    Posted 08-02-2017 at 02:05:05 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Need full choke to run
  • Plugged fuel filter. Start with the elbow at the carb and work up. Warped intake manifold. Fuel filter is an easy check. Far more intelligent people will be contributing soon.

    Dead Eye Dave    Posted 08-02-2017 at 08:00:39 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Need full choke to run
  • Is 2N supposed to have a filter? I thought not! Cleaning all three screens, cleaning gas tank and removing the filter may be in your future. DED

    HCooke    Posted 08-02-2017 at 08:52:59 [URL] [DELETE]        [Reply] [Email]  
  • Re: Need full choke to run
  • The screens are fuel filters!

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