Idle and air/fuel same thing?
05-20-04, 10:06 PM
#2
Nikki-Modder Rex-Rodder
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Long answer:
Adjusting the idle mixture is refering to adjusting the amount of fuel that comes into the idel circuit.
After anything over 1400 or so rpm, your engine is pulling enough vacuum to utilize the transition circuit, and then on to the main circuit.
By then, the vacuum forces that are being discussed pertain to the venturis and no longer to the idle circuit. However, the idle circuit is still functioning, but it effects the engine overall during main circuit operation so little that you could cut the idle circuit fuel off completely and you would never know or feel the difference. (...until you let off the gas and try to return to "idle", of course.)
The only way to control your "mixture" in the main circuit is to change jets. ...fuel jets, and air jets.
Air jets are the ones in the tops of the emulsion tubes, and they serve to bleed off vacuum signal to the fuel being "sucked" out of the main circuit. It so happens that in doing so, they alos aerate the fuel as it flows into the venturi, which helps to mist it.
Carbs are ****** cool!
Short answer:
The idle mixture screw is like an adjustable fuel jet.
Adjusting the idle mixture is refering to adjusting the amount of fuel that comes into the idel circuit.
After anything over 1400 or so rpm, your engine is pulling enough vacuum to utilize the transition circuit, and then on to the main circuit.
By then, the vacuum forces that are being discussed pertain to the venturis and no longer to the idle circuit. However, the idle circuit is still functioning, but it effects the engine overall during main circuit operation so little that you could cut the idle circuit fuel off completely and you would never know or feel the difference. (...until you let off the gas and try to return to "idle", of course.)
The only way to control your "mixture" in the main circuit is to change jets. ...fuel jets, and air jets.
Air jets are the ones in the tops of the emulsion tubes, and they serve to bleed off vacuum signal to the fuel being "sucked" out of the main circuit. It so happens that in doing so, they alos aerate the fuel as it flows into the venturi, which helps to mist it.
Carbs are ****** cool!
Short answer:
The idle mixture screw is like an adjustable fuel jet.
05-21-04, 01:32 PM
#4
RTFFAQ
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Ryan - For more info, I highly recommend clicking the WWW button down under Sterling's posts. I'm still trying to soak in everything Sterling has put out there, but it's a great resource.
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