[Tom Vaught]

Still trying to get the eye irritation in the left eye fixed up but thought I would add a bit more info on Holley carb theory in general. Some of this GENERAL info was taken from the February 1965 Car Craft article written by Don Francisco who was a great automotive theory writer.
The basic PHYSICS did not change after 53 years but the words used to describe carburetor circuits have changes somewhat.

" An Internal Combustion Engine is one in which the energy is a fuel, usually a liquid that evaporates slowly at normal temperatures and atmospheric pressures." TRUTH

"In its liquid form, gasoline will not burn, nor will the gas resulting from its evaporation until it is mixed with the correct proportion of AIR." TRUTH
"The small percentage of Oxygen in the air - (approximately one-fifth) supports combustion, and the mixture can burn with sufficient speed to be classified as an explosion" TRUTH

"When a mixture of oxygen and gasoline vapor burns in the engine's cylinder, a chemical change takes place in the oxygen and gasoline, and heat is created." TRUTH

"The chemical change produces several gases but the main two are Carbon Dioxide and Water Vapor". TRUTH

"As the HEAT of COMBUSTION raises the gases temperature, the GASES EXPAND and force the cylinder's piston down the cylinder and the piston's connecting rod rotates the engines crankshaft and the car's driveline." TRUTH

So here comes the KEY STATEMENT:

"The greater the WEIGHT of the AIR-FUEL MIXTURE in the cylinder before COMBUSTION, the HOTTER the COMBUSTION will be, and the more tightly the MIXTURE IS COMPRESSED, and the greater will be the PRESSURE that acts on the PISTON." TRUTH

So what did we learn from the words above?
1) That Carburetors control the MASS of AIR and FUEL that enters the engine (based on a control valve called a throttle blade).
2) The Carburetor has to MIX the correct ratio of air and fuel or the mixture will not explode and force the piston downward in the cylinder.
3) The carburetor has to have the ability to compensate for changes in the Mixture Ratio depending on the engine load vs the throttle blade position.
4) "Changing the liquid gas (fuel) into a GAS (VAPOR) and mixing the correct amount of air with that gas (vapor) so that the resulting mixture will burn in the engines cylinders are the DUTIES OF A CARBURETOR.

Mr Francisco says that there are 5 circuits or systems in the carburetor that allow it to do its job.

I will talk more about that as I continue to post his info vs current day knowledge.

Tom V.