Bowl Overflowing or Flooding (Aisan)

If you have fuel coming out the top of the carburetor, or around the throttle shaft, it indicates you’re getting too much fuel in the carb.

This list is by no means exhaustive, but these are the most common causes of carburetor flooding.

Needle and seat

  • inspect the carb surface for old gasket residue and clean carefully
  • use the gasket included in the rebuild kit
  • check for hairline cracks in the carb body where the seat threads in
  • needle is pulling out of the seat too far and not reseating properly
  • needle valve plunger spring collapsed (should 5mm on late carburetors, 8mm on pre 1971 carbs)

Purchase replacement needle and seats here

Float

  • float level (settings can be found in the kit instructions or rebuild manual)
  • leaking or saturated float
  • brass floats can be submerged in hot water, if you see bubbles, you need a new float.
  • worn float tabs
  • hinge holes or float pin excessively worn or rough

Replacement floats are available in our catalog here

Fuel pump pressure is too high and overpowering the caburetor

Air horn gasket damaged or incorrect

Air horn screws loose


Aisan Carburetor Parts
Updated on 04/26/2022

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