Regulator spring for adjusting carburettor engine revs compatible BRIGGS STRATTON MODELS: 21R507-0005-H5 21R602-0008-H1 21R607-0009-H5 21R807-0062-B5 21R877-0015-B1 31R507-0002-B1 31R507-0011-B5 31R577-0014-B5 31R777- 0010-B5 31R877-0015-G1 31R907-0018-G1 Part No.: 3-582 30270821 Original part No.: BRIGGS STRATTON 691842 ZC - ah m