Honda BF8, BF9.9 and BF10 Outboard Motors Shop Manual., Page 24Get this manual
SPARK TEST 1) Remove the engine coverDrain the gasoline from the
carburetorGasoline is highly flammable and explosiveIf ignited, gasoline can burn you severelyBe sure there is no spilled fuel near the enginePlace the spark plug away from the spark plug holeUnburned gas can ignite if it is left in the cylinderLoosen the carburetor drain screw to drain the carburetor thoroughlyPull the recoil starter several times to release the unburned gas from the cylinder before testing the spark plug
2) Remove the spark plug caps and spark plugs,
3) Pull the recoil starter several times to release the unburned
gas from the cylinders4) Attach the removed spark plugs to the plug caps
5) Set the ignition switch to the "ON" position (Remote control type only) and make sure that the emergency stop switch clip is engaged properlyGround the negative (-1 electrode (i.ethreaded part) of each spark plug against the thermostat cover bolt and pull the recoil starter rope to check whether sparks jump across the electrodes6Remove the spark plugs from the spark plug caps and install the spark plugs to the other cylinder spark plug cap and check spark for the other cylinder