1968 Evinrude Starflite 100 HP outboards Service Manual, Page 12Get this manual
TROUBLE CHECK CHART (CONT) TROUBLE POSSIBLE CAUSE APOWER HEADSee Section Lower bearing head loose (check end play) Carburetor and distributor not synchronized Throttle control lever bent (won't advance) Air leak at manifold gasketswarped manifold (backfires) Broken leaf valves (backfires) Cracked carbon seal (water in cylinders) Excessive carbon on pistons and cylinder head Stuck piston rings, or scored cylinder or piston BCARBURETORSee Section Old fueltoo much oil Carburetor adjustment(too leanbackfires) (too richexcessive fuel) Linkage screws loose Automatic choke not operating Air leaks at packing nuts Inlet needle and seat worn or sticky Incorrect carburetor float setting Incorrect orifice plug CFUEL PUMP AND TANKSee Section Faulty fuel hose (clamps or seals) (kinked) 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 DEXHAUST GAS ENTERING CARBURETORSee Section Exhaust cover screws leaking Cover plate gasket damaged Damaged exhaust housing seal Exhaust relief boot cut Adapter gaskets leaking Cracked exhaust housing Exhaust tube to cylinder screws loose or missing EOVERHEATING POWER HEADSee Section Exhaust cover gasket leaking Inner exhaust cover leaking Thermostat housing broken Pressure control valve damaged Power head gasket damaged Head gasket leaking (warped head) (water in cylinders) FLOWER UNITSee Section 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 bushing damaged Exhaust outlet damaged GEXHAUST GASES ENTERING COOLING SYSTEM See Section Pump impeller plate not sealing (bottom) Damaged water tube grommets or "0" rings Pump housing seal damaged (5" adapter seals) Exhaust outlet gasket missing Exhaust tube to adapter gasket damaged