by MECOA » Fri Oct 24, 2008 9:07 pm
If you have trouble with a rich idle and are unable to adjust it properly and you have checked all of the above, The inner tube of the mixture disk (where the slot and hole are in the picture to the left) may have excessive wear with the mating tube inside the barrel. The is a very close and precise fit. If it is loose it will not meter the fuel properly at idle. Kinda like a leaky faucet. At this point the carb should probably be replaced or at minimum the mixture disk and barrel replaced.
A good fit must also be maintained between the barrel and body. If this is worn, you will have air leakage and not be ably to get consistent idle or have the ability to shut the engine down when carb is closed.
If you can not obtain a consistent mixture or a rich enough high speed mixture check inside the spray bar. Many times something is plugging up the metering slot that controls the fuel flow for idle and midrange. Symptoms are not being able to obtain idle settings, not getting a rich enough high speed setting, and erratic settings.