Need help tuning Quickfuel carb
Main jets and PV on idle. There can be exceptions. Shrinker explaned hoiw this happens - its about the pressures and flow in the wells. My simplified version - which may not be terchnically as correct: If the relationship between the idle restrictions (IFR, and downstream) is close to the restrictions on the upstream feed side (Main jets) then there's going to be some effect. We can't compare areas directly because the main jet is fuel only, but the air bled into the wells changes the density. One more reason to have the Idle restriction submerged. Then as long as the idle restriction area is at least 4 times smaller than the main jet area, you can be more confident the main jet will have no effect at idle.