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  1. #1

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    Nikki carb question

    Hello,
    I own a Craftsman MTS5500 lawn tractor with a Briggs Intek VTwin 24 HP. I removed the carb bowl for float inspection after my crankcase was floaded with gas. I somehow lost one of the jets. The left and right are apparently different as they have different part numbers. Does anyone know the difference or should I just buy both?

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  3. #2

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    Re: Nikki carb question

    The difference is the size of the hole in the jet. Has something to do with the flow rate between the two cylinders. One cylinder has to have more fuel for the engine to run balanced.
    ILLINOIS ENGINE, BEECHER CITY, IL
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  4. #3

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    Re: Nikki carb question

    I "HATE" those Nikki carbs! The main jet is only held in by a small "O" ring. Gravity+vibration many times causes them to fall out. Your problem, however has little or nothing to do with the main jet. It is more than likely a bad/dirty float needle and seat that would allow fuel to enter the crankcase. A leaking float would do this too.

  5. #4

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    Re: Nikki carb question

    Yeah, I figured I would just check the needle/seat and clean it. Apparently I lost one of the jets. I guess I need to buy both as I don't know which one I have. Of course, no one local to me stocks them so I must order online and wait.

  6. #5

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    Re: Nikki carb question

    Got new jets, bowl gasket, and o-ring for fuel transer tube. Cleaned all and re-assembled. Engine starts and runs a short while only when choked. Will not run if choke is off. Any suggestions?

  7. #6

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    Re: Nikki carb question

    You need more fuel to air, check the gasket between carb and engine.
    "Information/Knowledge not shared will be lost for ever, now that I'am over 60 I will give freely any information that will help you out, you don't have to take it, that is up to you...! the word "thank you" will not cost you anything, so be nice sometimes and use it now and then"

  8. #7

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    Re: Nikki carb question

    Should that gasket be an issue on an engine with only 135 hours on it?

  9. #8

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    Re: Nikki carb question

    Did you take it off..? did you damage it in doing so..? and did you put it back on right..? It maybe one answer to your question, its a start..!
    "Information/Knowledge not shared will be lost for ever, now that I'am over 60 I will give freely any information that will help you out, you don't have to take it, that is up to you...! the word "thank you" will not cost you anything, so be nice sometimes and use it now and then"

  10. #9

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    Re: Nikki carb question

    Are you referring to the two intake gaskets? If so, I did remove the intake from the heads. It uses a rubber gasket with the plastic intake. As far as I know the were not damaged in the removal/replacement process.

    When it starts, it will run about 5 or 6 seconds then die. Could it be the fuel pump? I did check it first when my original problem of not starting began. It wasn't a steady stream, more of a pulse. Is this normal?

  11. #10

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    Re: Nikki carb question

    You better up the B&S engine numbers so that someone here may look it up for you.

    The fuel pump will pulse that is normal, and is mounted on the No. 1 cylinder shield and allows remote fuel tank installations. The fuel pump will prime at 12” (30.5 cm) maximum lift. and the fuel pump pressure should be around 1.5 psi (0.1 Bar ). The pump is operated by pulsating crankcase vacuum from the engine. The vacuum pulse line is installed on the No. 1 cylinder valve cover.
    Replace fuel lines and vacuum pulse line if stiff and brittle, and note: An air leak at the fuel pump pulse line hose connections will result in improper fuel flow.
    Last edited by EngineMan; 10-27-2012 at 04:27 PM.
    "Information/Knowledge not shared will be lost for ever, now that I'am over 60 I will give freely any information that will help you out, you don't have to take it, that is up to you...! the word "thank you" will not cost you anything, so be nice sometimes and use it now and then"

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