Carter B&B Carburetor Lacks Power From Idle To Cruise

posted in: carburetor | 2

Carter B&BI would look closely at the main discharge. See #28 on the diagram to the right. Remove the aluminum clean out plug. If you purchased our kit you will find one was added but bagged separate from the kit.

Using  a flat blade screw driver remove the discharge jet. These are often frozen into the carburetor. In these cases I would leave it in the carburetor and clean it out while in the carburetor. You may have to use thin wire to get the jet cleaned out. I know one person that drills the jet out by 1 size to accomidate the current fuel, but personally I would do that only if you are having an issue when accelerating. These jets are not available so damaging one is not an option here.

Make sure the passage going from the main discharge to the accelerator pump well is not clogged and clean.

# 30 is the pump check ball. Make sure it wasn’t left out and is clean. This is the bigger check ball of the 2.

On most B&B carburetors there will be a check ball at the bottom of the pump well along with a clip that holds it in. This is where the fuel enters the well. Make sure the ball is there and that it is working. When you fill the float bowl with (mineral spirits), the ball should lift up by the weight of the fuel and fill the well.

Put the main discharge back in along with the pump check ball and plug, then fill the pump well with fluid. Insert the accelerator pump and press down. Fluid should come out of the main discharge and into the carburetor throat. It’s difficult to describe just how much should come out, but you will see it drip out the bottom of the carburetor in a good quantity.

2 Responses

  1. Mark Robinson

    I’m having a slight hesitation from my 35 straight 6 motor. Trying to replace accelerator pump. Any suggestions?

    Mark

    • I don’t have much to go on like what carburetor are you referring to?
      I’ll assume it’s the B&B.

      The distributor advance can cause hesitation so check that out.

      Next would be the accelerator pump. That carburetor would have a leather cup. Be sure it didn’t dry out and curl up.
      With the engine off look down the carburetor bore. Pump the gas. You should see a good stream of gas come out of the main discharge.
      No squirt? Something is plugged. The main discharge can get plugged up because they seldom get cleaned. There is an aluminum plug on the side of the carburetor. With the top off look down at the main discharge. Remove the main discharge jet. They come out with a screw driver and they break easily, so if it doesn’t come out easily, then leave it in and clean it thoroughly.
      From there clean and blow out all of the passages.

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