The **Rochester 1 barrel carburetor** (B, BC, or BV) can use one or two checkballs.
ALL Rochester B series carbs use a 3/16â steel checkball in the pump discharge. Some B carbs also use a second checkball in the bottom of the pump well.
This particular carburetor only uses 1 check ball. There is only 1 hole in the pump well (A). This is the discharge hole. Gas is fed by running over the rib (B) into the well.
The main discharge is (C). This is where the fuel discharges when the accelerator pump is pushed down, accelerating. The 3/16â steel checkball sits at the bottom of the hole. The spring and T go above it.
If the fuel is feeding back into the well rather than pushing through the discharge, then the inlet checkball isn't sealing. Make sure you are using the aluminum ball. Tap the ball lightly with a brass punch to seat it. If by chance the ball is coming out of the hole completely, then look at the return spring to see if it is keeping the ball from coming out. You may have to spread the bottom of the spring out to fit better.
NOTE: Some of the B's have the intake ball on the bottom of the float bowl next to the well instead of inside the pump well. A screen fits over the ball to filter fuel from the bowl to the pump well and keep the ball in place.
The biggest check ball (3/16") is placed in the main discharge tube, the smaller aluminum check ball (5/32") goes into the bottom of the accelerator pump well (if needed) and the smaller steel check ball is placed in the main support well assembly.
