An adjustment screw apparatus

摘要

A fuel adjustment screw apparatus for a diaphragm-type carburetor comprises a screw member (4) having a shaft (4a) and a head (12) by which the shaft may be rotated, with a generally tabular open-ended housing (9) surrounding the head of the screw member. A cap member (10) is mounted in the housing and is movable axially of the screw member between a first position (as seen in figure 1) and a second position (figure 2). The cap member is held clear of the head of the screw member in the first position so that the screw member can rotate freely, and engages over the head of the screw member in the second position for rotation with the head. The housing has stop means (20) which is engaged by the cap member in the second position for limiting the angle of rotation of the head. Fig. 1.