Honda BF20A-BF25A, BF25D-BF30D Outboard Motors Shop Manual., Page 21Get this manual
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SPARK TEST
1Put the remote control lever or gearshift lever in the neutral position2) Disconnect all the spark plug caps from the spark plugs3) Remove one of the spark plugs from the engine4) Attach removed spark plug to spark plug capGround the negative (-1 terminal of the spark plug (threads)to the water jacket cover bolt as shown5) Using the ignition key, starter button or recoil starter, operate the electric starter and check to see if sparks jump across the spark plug electrode
NOTE On the remote control type, have an assistant operate the electric starter using the ignition key,