Question about Briggs & Stratton Briggs Stratton Lawnmower Lawn Mower Short Block

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Gas in crankcase, how? - Briggs & Stratton Briggs Stratton Lawnmower Lawn Mower Short Block

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  • glodanpow May 27, 2011

    Thanks, you confirmed my thoughts. I don't like it because the Carb is very hard to get to. It's on a rear mounted engine. I need to take the whole back end of the mower off to get to it. Mower is 12+ years old. I think its time for a trip to Sears.



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  • You need to get a needle valve and seat kit for your engine.
  • Make sure to change the oil right away.
  • Make sure to remember how or write down the governor linkage/ throttle body set up is.
  1. Remove the fuel line.
  2. Now remove the carburetor.
  3. Remove the fuel bowl by removing the fuel bowl nut.
  4. Flip the carburetor over and remove the float and needle valve by pulling the float pin out.
  5. Now you're going to remove the needle valve from the float.
  6. Remove the needle seat by pulling it out with a piece of coat hanger wire or blow the seat out with compressed air from an air compressor. Wear protective eyeware when doing this.
  7. Get the new seat. There will be grooves on one side of the seat. When installing the new seat, spray some WD-40 on it and install the seat so the grooves face down in the carburetor,. - The smooth part of the seat will be facing you. - Press in the seat with a flat punch until the seat bottoms out.
  8. Replace the needle valve with the new one in the kit.
  9. Since the size of your engine is not listed then should your Briggs & Stratton be an 8-22 HP engines, the seat is brass and pressed into the carburetor. It can only be removed with a Tap and a bolt. It's highly recommended that you take the carburetor in to a local shop and have them pull the seat out for you and reinstall the new needle valve and seat kit. Brass is a soft metal and very easily damaged. They know what they're doing.
  10. Assemble the float and needle valve to the carburetor and check the float level. Make sure the float is parallel to the carburetor body. If you have a pressure tester, connected it to the fuel fitting. This will tell you if the seat will hold gas or not. If the seat can hold 5 P.S.I., then it is ok. Install the fuel bowl and nut.

Regards, Tony

Posted on May 26, 2011

  • Iron
    Iron May 27, 2011

    • Your welcome. Yea, I hear the trip to Sear part. Good luck to you.





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1 Answer

Gas going into crankcase

Hi, Hb there are three ways in which gas can get into your oil tank/system:
1. Someone deliberately pours gas into your oil tank.
2. The vacuum petcock control rubber fails, which allows gas to flow from the fuel tank through the petcock, through the vacuum line into the intake manifold, then into the combustion chamber, where it seeps past the piston rings and into the bottom end where it gets pumped back into the oil tank.
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