Posted by David K on April 13, 2001 at 18:02:45:
In Reply to: Engine runs only on choke...? posted by Peter the blacksmith on April 12, 2001 at 20:56:44:
The carburetor is running lean, changing the air filter would be of no benifit, because dirty air filters act as a choke (enrichening the mixture). I have another theory that might explain the carb. to be lean.
If the carb vacuum diaphram is leaking air, or if the vacuum passage is clogged, or if the needle slide is stuck--any of these mentioned faults, will prevent the fuel mixture needle from lifting and not enrichening the fuel mixture.
Remember that the throttle cable only opens an air butterfly, the slide with needle attached is dependent on a vacuum diaphram for movement!