Honda BF75 BF100 Outboards Service Manual, Page 29Get this manual
HONDABF75BF 100 11CYLINDER COMPRESSION CHECK
(1) Remove both spark plugs and connect compression tester to the cylinder by screwing the adaptor into the spark plug hole(2) With the throttle valve wide open, and the engine stop button depressedor wire attached to ground the coil primary terminal, crank the engine several timesNote the maximum reading on the compression gaugeCAUTION: The ignition coil may be damaged by cranking the engine with the spark plugs removed, unless the engine stop button is depressed or the coil primary terminal is otherwise grounded