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  5. 2 Jet Flooding
Flooding is when gas is coming over the top of the carburetor. This simply means there is too much gas getting into the float bowl. Here is a list of things that can cause this. Not in any order.

  • Test the needle & seat.
  • Check fuel pump pressure. You will need to check your motors manual for the correct setting, but should be about 4 - 4.5 lbs.
  • Look at the needle viton tip. They can get damaged if too much pressure are put on them adjusting the float.
  • Clean the residue off the viton tip with mineral spirits.
  • Does the seat have 2 gaskets by mistake, or are the gaskets damaged, or is the float bowl cracked around the seat. Any of these problems would allow the the fuel to leak past the needle & seat with nothing to stop it?
  • Holding down the needle into the seat gently, try blowing a small amount of air in the inlet. Is it holding?
  • Does the power valve have a gasket under it, only 1 gasket and it is not damaged, or cracked?
  • Move the float up & down to see if it is hanging up somewhere. Make sure it isn't rubbing on the side of the bowl, or the bowl gasket.
  • Most of the 2 jets use a clip to clip the float to the needle. Make sure the float pulls the needle straight and that it doesn't bind the needle.
  • Is there dirt in the needle. Dirt may be coming up for the gas tank, regardless of the filter.
  • Power valve - Your power valve should move up/down easily. It would flood if the power valve was stuck open due to the pin staying down, or the piston staying down. Take the power valve out and blow through it while pushing the stem in & out. You shouldn't be able to blow through when the pin is up. Follow the vacuum hole going to the power piston to make sure it is clear.
  • When the vehicle has sat for 6 or more months, the inside of the carburetor has probably varnished up. Once the fuel turns not only does the carburetor have to be cleaned, but also the gas tank and fuel lines must be cleaned, otherwise crud will get back into the carburetor and you will start all over.
    • Once this happens you will need to make sure every passage is clean. Clean the carburetor by soaking in simple green for 2 hours. Wash out with hot water if possible and blow out all passages. Spray some spray carburetor cleaner through the passages. This will break down the varnish. Test each passage to make sure it goes all the way through.
2 Jet Parts

Rochester 2 Jet Parts

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