Aisan Troubleshooting

Runs Rich

  • Check float level.
  • Test the needle & seat for leaks
  • Weight the Nitrophyl float for proper gram weight. Weights are different depending on which Aisan you have. A carburetor number would be required.
  • For a brass float, immerse in hot water and look for bubbles.
  • If the vehicle has been sitting for months, then the gas has probably varnished the inside of the carburetor. A carb rebuild would be in order, gas tank removed and cleaned and fuel lines cleaned or replaced.

Stalling, Rough Idle or Hard Starting

Could be caused by the Thermostatic Valve equipped on some vehicles.

Aisan Carburetor Thermostatic Valve

As the valve opens, it allows outside air to flow directly into the intake manifold, leaning out the rich air fuel mixture. Valve starts to open when engine compartment temperature reaches 140 F, or 60 C and fully opens at 167 F, 75C.

Updated on 04/13/2022

Was this article helpful?

Related Articles

Need Support?
Can't find the answer you're looking for?
Contact Support