1968 Evinrude Speedifour, Starflite 85HP Service Manual, Page 12Get this manual
TROUBLE TROUBLE 2LOSS OF POWER(Assuming Ignition
(CONT) CAUSE POWER 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 manifo1d (backfires) Broken reed valves (backfires) Cracked carbon seal (water in cylinders) Excessive carbon pistons and cylinder head Stuck piston ringscored cylinder piston CARBURETORSee Section Incorrect fuel mixturetoo much oil Carburetor adjustment(too leanbackfires) (too ri ch excessive fuel) Linkage screws loose Automatic choke not operating Air leaks at packing nuts Inlet needle and seat worn sticky Incorrect carburetor float setting Incorrect plug FUEL PUMP ANDSee Section Faulty fuel hose clamps ring damaged seals) (kinked) Fuel tank filter plugged Fuel filter restricted Fuel and vent valves not opening Valves not operating
GAS ENTERING CARBURETOR See Section Exhaust cover screws leaking Cover plate gasket damaged Damaged exhaust housing seal Exhaust relief boot cut Adapter gaskets leaking racked exhaust housing Exhaust tube to cylinder screws loose missing Impeller housing seal leaking Impeller housing cover seal damaged