Quote:
Originally Posted by stoki  What is causing this? |
Carburetors rely on gravity to function. When you subject a carburetor to negative Gs, the float will rise up and close the needle valve in the fuel inlet, cutting off the flow of fuel. Also, the fuel already in the float bowl may drift away from the passage leading to the carb's main discharge nozzle, which will lean out the mixture. The lean mixture will cause the engine to run rough due to the uneven fuel/air distribution among the cylinders. Each cylinder will put out a slightly different amount of power, causing the roughness.
Figure 5-7 in FAA-H-8083 shows a carburetor cutaway. You can see how negative Gs can affect the float and the fuel in the float bowl.
Quote:
|
Or is it the oil in the sump, somehow interfering with cylinder movement slowing down your RPM?
|
Eh, I doubt it.
Quote:
|
Is this a hazard, or dangerous?
|
Well, if you do it long enough, the engine will quit. There also might be a chance of detonation if you are operating at a high power setting with an improper mixture. Reduce power below 70% or so and you can't cause detonation with the mixture. Running rough isn't good for it, though.