That 3/8" float measurement is just a guide to get you in the ballpark. Once you lower it to where you no longer see raw fuel running in, you will very likely not notice much difference in the way it runs if you lower it a little more. However, the lower you go, the leaner the mixture will be so you will have to tweak the mixture screws a little. Basically, if you get it too low or too lean, you'll feel the hesitation and stumble on acceleration but fuel mileage will improve slightly. If you have it too rich, but not to the point of running over, you won't notice it in the engine performance. It's doubtful you'll even see black smoke from the tail pipe. The only way to find that wasted fuel is with an exhaust gas analyzer.
I don't think your idle circuits are plugged. Those are the same jets used for high speed when the metering rods lift up. Half of the cylinders wouldn't run if one of those were blocked.
Something else I forgot about, and now my memory is failing me, I think there should have been two small metal balls in the accelerator pump circuit. One of them is held down by gravity, but when you press the gas pedal the rushing fuel pushes that ball off its seat to let the gas squirt into the venturi. If that ball is missing, vacuum will continue to draw in raw fuel and cause a flooding condition. That will appear to partially clear up if you lower the float since it's harder to suck that fuel up the passages and into the air flow but it will still be flooding at higher vacuum such as when coasting, and you'll have a severe stumble at low vacuum when accelerating.
If you pinch the fuel hose and the engine smooths out within about half a minute or less, that suggests the float is just too high. If it continues to act flooded or way too rich until it almost runs out of fuel, check for a missing check ball in the accelerator pump circuit. As the fuel is used up in the float bowl, the engine will run better and better until it stalls.
Wednesday, June 22nd, 2011 AT 9:23 AM