1971 Evinrude 40HP outboards Service Manual, Page 13Get this manual
TROUBLE CHECK CHART (CONT) TROUBLE POSSIBLE CAUSE ASPARK PLUGSSee Section Cover or inner terminal damaged (spark plug point out of H.Tlead) Faulty leads Looselow torque Incorrect hea range Defective (cracked insulator) BMAGNETOSee Section Incorrectly adjusted points Loose wiring Coil or condenser damaged (loose) Fibre breaker block worn Points dirty or pitted Sheared fl ywhee key 4POOR PERFORMANCE ON BOAT AINCORRECT PROPELLER Incorrect tilt angle Incorrect fuel mixturetoo much lubricant(smoking) Remote controls incorre ctly ad justed Propeller hub slipping Bent or worn propeller Exhaust outlet damaged Bent gear housing or exhaust housing (broken driveshafts) Altitude hors epower loss Catamaran (single engine)venturi effect Exhaust leaks Overheating BCAVITATION Protruding hull attachments Keel too long Bent propeller (vibration) Transom too high CBOAT Improper load distribution Marine growth on bottom Added weight (water absorption) Hook in bottom ASTARTING CIRCUITSee Section Loose or corroded battery connections Safety switch inoperative (loose) Throttle advanced too far Poor or broken battery connections Weak or shorted battery Defective key or starter switch Jammed starter drive Damaged starter drive parts Worn brushes Broken brush spring Open circuit in solenoid Burned commutator Broken field terminal Shorted or open windingsarmatu re or field BEXCESSIVE STARTER CURRENT DRAWSee Section Worn or dry armature shaft bearings Excessive friction in engine Brushes not seating Dirty or corroded commutator Loo se pole pieces Shorted armature or fie ld Bearing heads buckled