1978 Evinrude Outboards 9.9/15HP Service Manual, Page 15Get this manual
TROUBLE CHECK CHART TROUBLE POSSIBLE CAUSE AFUEL SYSTEMSee Section Fuel line improperly connected Engine not primed Speed control not advanced (throttle closed) Engine flooded Old fuel Clogged fuel filter Choke not closing completely Choke spring broken or disconnected Fuel system faulty BIGNITION SYSTEMSee Section Spark plug leads crossed or reversed Linkage improperly adjusted Sheared flywheel key Ignition system faulty Cable plugs disconnected or incorrectly connected CSTARTERSee Section and Starter circuit faulty Neutral start switch (faulty or adjustment) DNEUTRAL START Gear shift not in neutral Manual start lockout adjustment APOWER HEADSee Section Carburetor and magneto not synchronized Throttle control lever bent (won't advance) Air leak at manifold gasketswarped manifold (backfires) Broken leaf valves (backfires) Worn main bearing seals Excessive carbon on pistons and cylinder head Stuck piston rings, or scored cylinder or piston Recirculating system plugged (check valve See Section 3) BCARBURETORSee Section Poor fuel mixtoo much lubricant Carburetor adjustment(too leanbackfires) (too richexcessive fuel) Choke not opening Air leak at low speed needle Inlet needle and seat worn or sticky Incorrect carburetor float setting Dirt in high speed orifice Altitude horse power loss CFUEL PUMP AND TANKSee Section Faulty fuel hosekinked Fuel tank or pump filter plugged Fuel filter restricted Fuel and vent valves not opening Valves not operating Diaphragm leaking or damaged Fuel system hoses plugged "0" ring damaged in fuel line connector DEXHAUST GAS ENTERING CARBURETORSee Section Exhaust cover screws leaking Cover plate gasket damaged Damaged exhaust housing seal Cracked exhaust housing EOVERHEATING POWER HEADSee Section Exhaust cover gasket leaking Inner exhaust cover leaking Power head gasket improperly installed or damaged Head gasket leaking (warped head) (water in cylinders) Pump housing "0" ring