1978 Evinrude Outboards 9.9/15HP Service Manual, Page 16Get this manual
TROUBLE CHECK CHART (CONT) TROUBLE POSSIBLE CAUSE Water intakes obstructed Pump housing air bleed restricted Water passages obstructed Pump plate not sealing (bottom) Pump impeller damaged Pump housing or plate worn Pump housing seal worn (driveshaft grooved) Water tube grommet damaged FLOWER UNITSee Section Propeller hub Slipping Bent or worn propellerconverging ring missing Bent gear housing or exhaust housing GEXHAUST GASES ENTERING COOLING SYSTEM See Section Pump impeller plate not sealing (bottom) Damaged water tube grommet or "0" rings Pump housing seal damaged (5" adapter seals) Exhaust tube to water tube grommet Seal between gearcase and exhaust housing ASPARK PLUGSSee Section Cover or inner terminal damaged (spark plug terminal point out of HTlead) boot Faulty spark plug leads Looselow torque Incorrect spark plug Defective (cracked insulator) BIGNITIONSee Section Loose wiring Damaged ignition coil leads Faulty sensor coil Faulty charge coil Faulty power pack Sheared flywheel key Cable plugs loose Loose armature plate screws