Tilt the main body slightly to keep the fuel inlet needle from falling out of its seat. Carefully place the float assembly and float spring in the fuel bowl. To install the float and float spring in the main body, insert the long end of the float spring into the…
At idle and low speed the manifold vacuum is at it’s highest which brings fuel in from the idle circuit. Do not confuse this with venturi vacuum. Venturi vacuum at idle isn’t strong enough to pull from the main system so additional fuel is necessary. Both barrels have identical idle…
With the engine running, air is drawn in by the downward stroke of the pistons through the carburetor venturi. This creates a vacuum in the venturi pulling fuel from the bowl. Once past idle speed, fuel flows from the float bowl through the main jet and into the bottom of…
Dashpots are used on the 1901 with automatic transmission.
Fuel enters the Holley 1901 through the fuel inlet. When the fuel lowers and the float drops, the fuel valve pulls out of the seat and allows fuel to enter the float bowl. Once the float bowl fills to a specified amount the float raises and forces the float valve…
The WW float is used to maintain the correct level of gas while idling and at high speed. Fuel enters at the fuel inlet. As gas is used, the float drops allowing the needle valve to pull out of the seat, allowing gas to enter the bowl. Once the bowl…
Rough Idle Check for vacuum leaks, intake manifold to cylinder head, carburetor mounting gasket. Uneven compression. Do a compression test on the cylinders. Leaking valve seats. Valve tappets out of adjustment. Weak spark, bad wires, plugs, points, distributor cap. Timing Bent or scored idle mixture screw. Idle mixture passage partially…
The amount of fuel supplied to an engine is controlled by the size of the power jet, the position of the power adjusting needle, and the difference in air pressure between the fuel bowl chamber and the venturi. However, in many engines the mixture must be leaned out additionally during…
How it works With the throttle valve (6) in slow or just off slow idle position, fuel rises up through the nozzle (14) and out the nozzle air bleeds (15) to fill the accelerating well (16) to approximately the height of the fuel level in the fuel bowl (1). As…