Running rich , the story continues

[drolston]

Seems like a lot of confusion here… the two screws being referred to as “Idle Adjustment” have no control over fuel delivery. They are air adjustments. Typically they should be 1.5 to 2 turns out from closed and are only effective at idle. They will affect idle smoothness which might resemble speeding up.
Best set using a vacuum gauge and adjusting to the highest and most steady needle reading. Typically 15” to 19” of vacuum while idling.

Idle speed is controlled by the screw on the bell crank where the accelerator rod connects to the carburetor.

Fuel control is by jetting and power valve.

Sounds like too much fuel pump pressure and or possibly the float valve not shutting off.

Just watched Charlie Prices's video again. The idle adjust screws actually do control the fuel flow that exits below the throttle plates. The throttle stop screw you refer to controls the minimum air flow past the throttle plates.

 

[FlatTopFreddie]

If the idle mixture screws are closed, how does the idle circuit get fuel?

 

[pistonbroke]

That Freddie is why I was saying earlier I thought he was running on his main circuit not the idle circuit. Bcatcmc, Are you making these adjustments with all the linkage off the carbs? There should be no gas pedal choke or hand throttle hooked up to the carbs when making these adjustments or you will be chasing your tail in circles. Tim

 

[jeepguy1948]

Personally I have always preffered Idle Mixture Screws that adjusted fuel. That’s a lot easier for me to get my head around then air.

 

[bcatcmc]

no linkages, no difference, needle jets pristine, Mr Stromberg now on the case ,will report in if anything of substance comes up.

 

[FlatTopFreddie]

Here is a good article that explains the circuits in a carburetor. The Idle circuit including the mixture screws is explained very well… even though the focus is 4barrels, the theory is the same.

https://www.hemmings.com/stories/article/the-lost-art-of-2