Honda BF75 BF100 Outboards Service Manual, Page 99Get this manual
HONDA BF75BF100
bSpark Advancer
The spark advancer is housed in the cam pulleyWhen engine speed increases, centrifugal force moves the advancer weight! (11) outward, causing the rotor {10) to turn in the direction shown by the arrowsThis advances ignition timing in proportion to engine rpm