The Rochester carburetor float is contained inside the carburetor itself, so the top of the carburetor must first be removed in order to make any adjustments. If the float level is too high, fuel mileage suffers. If it is too low, performance is poor. Another common problem is the float becomes saturated with fuel and is too heavy. This allows fuel to continually flow inside the carburetor. When this happens, fuel spills into the engine and may cause a fire.
Remove the air cleaner by loosening the wing-nut that holds the air cleaner lid in place. Lift the air cleaner off and disconnect any vacuum hoses that are attached to the cleaner body.
Operate the accelerator linkage and notice the rod that operates the light green pivot arm that sits on top of the carburetor. This arm operates the accelerator pump. Use a small punch and small shop hammer to tap on the pivot pin that holds the arm in place. It is not necessary to completely drive out the pin, rather, just enough to free the pivot arm. When the arm is lose, lift it up, disconnect it from the linkage and set it aside.
Use a screwdriver and remove the small screw that holds the choke rod to the upper choke plate. It is opposite the accelerator pump on the passenger side of the engine. This rod is easily dislodged from the linkage inside the choke coil, so use caution when removing it. If it becomes disconnected, disassembling the choke coil and housing is often necessary to replace the rod.
Remove the secondary metering rods that are in the middle of the carburetor. They are held in place by a small screw that connects them to a cam that lifts them up when the throttle linkage is operated. Operate the throttle lever linkage and notice the cam. Remove the small screw on top of the cam that holds the rods in place. Lift the rods out of the carburetor.
Remove all the screws that hold the top of the carburetor in place. Remove the two bolts at the front of the carburetor that mount the carburetor to the engine. Lift the top of the carburetor off and remove the float bowl gasket. The float will lift out. It is held in place by a metal pin with a curved handle that loops back. When the float is lifted out, the needle that regulates the fuel flow will follow. It is attached to the float with a small retaining wire that is specially formed to clip the needle in place.
Adjust the float by bending the tang that is on the float that the needle rides against. Measure the float while it is in place in the float bowl by pressing down on the mounting end and closing the needle. Make the measurement at the opposite end by measuring the distance from the float body to the top of the carburetor. It is necessary to reference specifications for the carburetor model to determine the exact measurement number. The measurement is very precise, normally given in 1/64-inch increments.
Reassemble the carburetor. Install a new float bowl gasket and replace all the bolts and screws. Do not overtighten the screws and warp the carburetor body. Insert the accelerator pump lever back into place and use a screwdriver to lever the pin back into place. Reattach the choke screw to the choke plate.
