If you are passionate about cars, you probably know about constant choke carburetors, constant vacuum carburetors, and multiple venturi carburetors. However, did you know that there is also another type of carburetor that is rarely mentioned? We are talking about electronic carburetors. To be fair, electronic carburetors are not a…
Holley Standard Main Jets Jet No. Drill Size Jet No. Drill Size 40 .040 71 .076 41 .041 72 .079 42 .042 73 .079 43 .043 74 .081 44 .044 75 .082 45 .045 76 .084 47 .047 77 .086 48 .048 78 .089 49 .048 79 .091 50 .049…
Some Autolite 4100 carburetors have 4 vent tubes sticking out of the top. These are used to vent the primary and secondary float bowl. Left unvented, the gas could siphon out of the float bowl and into the bores causing a rich condition. With the top turned over, this image…
Some BB-1 updraft carburetors have a main jet adjustment. This is so the carburetor can be adjust to different engines. Generally this would be a replacement carburetor. To adjust – 1st adjust the idle mixture. The main jet adjustment is done basically the same way except instead adjusting at idle…
Fast Idle and Unloader During the warm-up period, it is necessary to provide a fast idle speed to prevent engine stalling. This is accomplished by a fast idle cam connected to the choke shaft. The choke trip lever contacts the fast idle cam. The fast idle link attached to the…
Idle By-Pass Assist Some BBD units incorporate an idle by-pass assist. This passage goes through the main body, and the body gasket. Through a passage in the throttle body and enters below the throttle valve. This extra air through the by-pass allows the throttle valve to close a little more…
The model BBD is a BB design, dual carburetor with low overall height. Accessible adjustments and removable subassemblies. It has been supplied in both 1 ¼ and 1 ½ inch S.A.E. flange sizes. Five conventional circuits are used. They are: Float circuit Low speed circuit High speed circuit Pump circuit…
Sometimes referred to as a Holley Teapot As the throttle opening is increased upon acceleration, the air flow through the carburetor responds almost immediately. There is, however, a brief interval before the fuel, which is heavier than the air, can gain speed and maintain the desired balance of fuel and…
On Mercury vehicles equipped with automatic transmissions, a dashpot is incorporated with the carburetor to prevent loading of the engine when the accelerator pedal is suddenly depressed and released. The dashpot accomplishes this by retarding the closing rate of the throttle plates in the last few degrees of their rotation…
The spark advance mechanism of the Holley pressure type distributor is controlled by a vacuum operated diaphragm operating against the tension of calibrated springs. The degree of spark advance is primarily regulated by the strength of the vacuum acting on the diaphragm. The vacuum is transmitted from two interconnected passages…