The throttle pedal is connected to the butterfly valve in the carb - or throttle bodies. The valve position throttles the flow of air (hence the name) so if your foot is off the pedal, the valve is shut thus reducing the flow of air to almost nil and consequently the fuel drawn into the flow of air is also v small thanks to Bernouilli. Some (all?) carbs have idle jets to allow proper fuel flow at idle.Russ said:"is the fuel directly affected by thottle position or is your throttle position just indicative of how much fuel per revolution you use"?
OK here's two things to think about. And, to keep things simple, just imagine a single carb setup (mutlipe carbs and FI are too complicated for me at this time of night.)Russ said:So its a combination then, throttle position affects air flow, but if the butterfly is part open at 2000rpm its drawing less fuel than at 6000rpm?
I have sat down and thought about all this, but I'm still not entirely certain. I'm thinking at 6000rpm with a perfect intake and exhaust system you'd use 3 times as much fuel as at 2000rpm.