BUSHING 2525617 - Caterpillar

Adjustments
Turn the power adjustment to center between "R" (rich) and "L" (lean). Fuel mixture adjustments are made by changing the gas pressure from the line pressure regulator. See the topic, LINE PRESSURE REGULATOR.
CARBURETOR ADJUSTMENTS (Carburetor removed for better illustration)
1-Idle adjustment screw. 2-Throttle stop screw.Turn idle adjustment screw (1) four full turns open (from the closed position).Turn throttle stop screw (2), to obtain desired idle speed. Recommended low idle is 425 RPM. (750-800 RPM when used with an electric set).Throttle Valve Synchronization (Engine not operating)
If the throttle valves are not opening simultaneously on both carburetors, the load will not be balanced between the left and right banks of the engine, and uneven operation can result.1. Disconnect governor linkages at each throttle shaft lever (2).2. Turn the low idle throttle stop screw (1) out until each throttle will close without allowing the screw to touch the stop. Slots (3) cut in the end of the throttle shaft indicate the position of the throttle plate.3. Adjust each low idle throttle stop screw (1) so it will just touch the stop with the throttle plate remaining closed. Throttle shaft lever (2) must be in the same relative angular position to the throttle plate [slot (3)] on both carburetors.
THROTTLE VALVE SYNCHRONIZATION (Carburetor removed for better illustration)
1-Low idle throttle stop screw. 2-Throttle shaft lever. 3-Slot.4. Move the governor control lever to the OFF position.5. Adjust the length of the governor-to-carburetor linkages so both connections can be made with the throttle plates completely closed, and the governor weights fully closed.6. Connect both linkages to throttle shaft levers (2).7. Set both low idle throttle stop screws (1) for the recommended low idle.Throttle Valve Synchronization (Engine operating)
Check that each regulator is maintaining the required pressure for the fuel being used and that there is equal pressures to both carburetors.Connect one end of mercury manometer (2) to connection (3) and the other end to the similar connection on the other side of the engine.
BALANCING MANIFOLD PRESSURE
1-Rod. 2-Mercury manometer. 3-Connection. A-Mercury level. B-Mercury level.The 4S6553 Instrument Group also provides a means to make this quick check. This group contains an instantaneous reading tachometer and a gauge for reading inlet manifold pressure. Special Instructions FE036044 are included with this group.
4S6553 INSTRUMENT GROUP
1-Lid. 2-4S6997 Manifold Pressure Gauge. 3-Pressure tap fitting. 4-4S6992 Differential Pressure Gauges. 5-4S6991 Tachometer. 6-Zero adjustment screws. 7-8M2743 Gauge.With the engine operating and governor control lever in LOW IDLE SPEED position, adjust length of rods (1). Increase engine speed to full load and check gauge reading. Adjust if necessary. The correct adjustment exists when gauge readings are within 4.1 in. H2O (104,14 mm H2O) or .3 in. Hg (7,62 mm Hg). This is same as difference in mercury level (A) and mercury level (B) in manometer. Do not vary the regulator adjustment to synchronize the inlet manifold pressures. Synchronization is accomplished by linkage adjustment only.Line Pressure Regulator
A line pressure regulator is required to maintain a constant inlet pressure differential between the gas and air to the carburetor. The pressure