A-B1693863-AI BASE-A/C PRIMEROne New Aftermarket Replacement A C Primer Base Fits Briggs and Stratton Small Engines This air cleaner primer base mounts between the carburetor and the air filter housing on Fits Briggs and Stratton small gasoline engines. It houses the primer bulb and circulates fuel through the carburetor during cold starts, allowing the engine to fire reliably. A cracked, deteriorated, or leaking primer base is a common cause of hard starting and rough running on