Yamaha Outboard Motors Factory Service Manual F6 and F8, Page 498Get this manual
TROUBLE SHOOTING FOR PEAK VOLTAGE TROUBLE SHOOTING FOR PEAK VOLTAGE 1Items Poor starting Symptoms No firingThe starter motor cranks the engine, but no firing takes place in the cylinderFiring takes place in the cylinder, but the engine stops soonStart-up time is too longThe engine will not start-up easilyThe engine speed is not stable at idleThe engine stalls when the throttle lever is openedThe engine stalls after it is warmed-upThe engine does not run smoothlyThe engine speed drops during accelerationUnstable idling speed Unstable engine speed
Check the ignition system1) Check the harness couplers toignition coil, CDI unit, pulser coil, and charge coilNG OK 2) Check the spark gapOK NG 3) Check the plug capNG OK 4) Check the ignition coilsNG OK Out of specification Replace Out of specification Replace Above specification Replace the spark plug