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Subject: Runs fine then dies after 10-15 mins

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fuesselfc    Posted 08-02-2017 at 11:56:41 [URL] [DELETE]        [Reply] [Email]  
  • Runs fine then dies after 10-15 mins
  • This is a recent issue that just started. Ran fine all spring till last weekend. 49' 8n 12v for stats of tractor, runs fine and then 10-15 mins into usage it will start to bog down and then eventually die within about 30 secs. I can pull choke in and out and it keeps it running enough to get it back to garage. Spark is fine on all 4 cylinders. Fuel I may have little bits of rust in tank and am afraid some may get into carb causing issue. Sometimes bogging down will clear itself and that's why I think this may be an issue. I have cleaned carb, and yesterday replaced metal fuel line over engine to a black fuel line with a inline filter so I can see fuel getting to carb. After this idea ran tractor and same issue happened. I will clean carb again and see how it goes. Ideas if problem persists? Thanks for any suggestions. I do t have a lot of technical mechanical speak so as much lehmans terms is better for me to understand.

    Jack - Iowa    Posted 08-03-2017 at 08:05:02 [URL] [DELETE]        [Reply] [Email]  
  • Re: Runs fine then dies after 10-15 mins
  • A blockage in the intake air will give your symptoms. When it starts bogging down, slide the rubber connector boot back from the carb air intake.

    Good Luck,

    Jack

    Rustyal    Posted 08-02-2017 at 21:34:16 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Runs fine then dies after 10-15 mins
  • A carb issue would not take 10 minutes.

    John77046    Posted 08-02-2017 at 17:21:13 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Runs fine then dies after 10-15 mins
  • Sounds like the coil if a front mount.

    It runs till warmed-up then misses till you back to the garage. Cools off while you are trying to fix gas problems. Then works till warms up and then misses again. Back to the garage and cycle repeats.

    Hope this helps

    Bruce (VA)    Posted 08-02-2017 at 12:54:11 [URL] [DELETE]        [Reply] [Email]  
  • Re: Runs fine then dies after 10-15 mins
  • You need to answer 2 questions before you do anything else:

    With the bolt in the carb bowl removed and the gas on, will the fuel flow fill a pint jar in less than 2 minutes?

    Next, get out your adjustable gap spark checker * , open the gap to 1/4", hook it up, turn the key on and crank the engine. Does the spark jump 1/4"? Post back with the answers.

    And do not buy a new part for the tractor until you can answer this question: how do I know the part on the tractor is defective? Replacing the oem fuel line with a rubber one and an in-line filter has just created a new set of problems for you; see tip # 15. Resist the temptation to fix things that are not broken.

    * Don't own an adjustable gap spark checker? Buy one! Not a test light! Until then, take an old plug, open the gap 1/4" ground it to the head & look for spark. Itís not the color of the spark that counts; itís the distance it jumps.

    fuesselfc    Posted 08-02-2017 at 16:54:20 [URL] [DELETE]        [Reply] [Email]  
  • Re: Runs fine then dies after 10-15 mins
  • So are we checking fuel pressure really to see how much gas is flowing down to carb? I can say I don't think I have had a full gas tank during this issue. Maybe I should fill it up! Will get my. Will get my buddy who is a mechanic to check this spark gap for me. Follow back up soon. Thanks for the #15 tip, makes very good sense Bruce!!

    Bruce (VA)    Posted 08-02-2017 at 17:37:16 [URL] [DELETE]        [Reply] [Email]  
  • Re: Runs fine then dies after 10-15 mins
  • Not really checking fuel pressure as it does not have a fuel pump. You're checking flow.

    And if you ask your buddy to check spark gap he will pull the spark plugs! You're checking spark intensity, not gap. It's the distance the spark jumps at the plug that gives you the info you want. It takes about 22kv to jump ľĒ in the open air. Remember, itís 14psi outside of the engine & about 90psi at a 6:1 compression ratio in the cylinders & compressed air creates electrical resistance, so you really need the 22kv to fire the plugs when the engine is running.

    michael    Posted 08-03-2017 at 21:45:19 [URL] [DELETE]        [Reply] [Email]  
  • Re: Runs fine then dies after 10-15 mins
  • Bruce, to answer question one on fuel it only gives me about 3/4 cup or 6 oz of fuel per 2 minutes. So where do I go from here. I hear something about a screen in the tank?

    Bruce (VA)    Posted 08-03-2017 at 23:22:51 [URL] [DELETE]        [Reply] [Email]  
  • Re: Runs fine then dies after 10-15 mins
  • Check out tip # 39. You have a 60+ year old tractor. Trying to work on it w/o the manuals is not fun.

    See tip # 45; there are 3 fuel screens you need to check.

    Start w/ the screen in the brass elbow at the carb. (see tip # 56) Then check the screen in the top of the sediment bowl. (see tip # 70)

    If that doesn't fix the problem, then it's time to remove the sediment bowl for a good cleaning of that screen.

    Little Ed    Posted 08-03-2017 at 22:47:05 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Runs fine then dies after 10-15 mins
  • Check the filter in the tank atop the sediment bowl/shutoff assembly. Mine did not have one, and that allowed a bug to get caught in the passage ways of the shutoff, and restrict the flow enough that it took a few minutes of hard work to run out of gas. It would then catch up when I would idle it down. had me scratching my head for a few minutes on that one

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