This is a Briggs Pulsa Prime tank-mounted carb on 10L900 Series Engine with vertical crankshaft (#1). Remove air filter by removing single center screw.
There is a round fiber gasket between the air filter base and the carb. (#2).
Crankcase breather tube elbow has been removed (#3).
Remove throttle governor spring (#4). The tang to which the spring attaches at right can be bent to adjust engine speed. Bend it toward the carb for lower speed.
Remove 3/8in. screw at right mounting bracket (#5).