Rochester Carburetor Rebuild - Fixing Broken Chains

Rebuild kits come with "standard" main metering jets (.051-inch for 216s, .058-inch for 235s). If you want to enrich or lean your carb,...

...you'll need to locate the appropriate jet sizes (one step increment each way). The power valve assembly will use the smaller of the check balls. Make sure it moves freely without excess play.

Once the air horn is fully cleaned and properly reassembled, you'll need to set the float levels. Fortunately, most kits come with combo gauges like this; otherwise, you can use a small straightedge with 1/32-inch increments. Most Chevy applications will require the float to be set at 1 9/32-inch (top of the float to the air horn's gasket).

To determine float drop, flip the air horn over upright and set the hang distance at 1 3/4 inch (same measuring points). Ensure that both floats are positioned evenly and do not touch the sides of the air horn during movement.

Adjusting the float for both steps is done with the two rear seat tangs. If you have any doubts about the condition of the floats, submerge them into fuel (or shake them if the carb was recently on the engine) to check for leaks.

Next, adjust the choke rod by turning the idle screw until it touches the second step (from bottom) on the fast idle cam. Using a 5/64 drill bit (1/16 for 216s), bend the choke rod until the bit fits snug between the choke valve's bottom edge and the air horn's inner bore.

To adjust the unloader, move the throttle to the wide-open position and, using a 15/64 bit (for both the 216 and 235) placed between the air horn and the bottom of the choke valve, bend the tang on the throttle lever accordingly.

After the air horn and main body are reunited, the Auto Choke can be set. (Note that the choke assembly wasn't removed-do so only if any parts need to be replaced.) Stat covers are marked individually with a single groove to correspond with the adjustment notches on the housing-the final position of the Rochester "name" can be crooked!

After final idle vent adjustment and double-checking everything, you should be good to go-theoretically. Oftentimes, further adjustments will be required once the carburetor is installed back on the engine-and that goes beyond the carb itself, as other associated chain links such as vacuum, fuel supply/source, and even ignition can play a role in preventing your engine from running right.