1971 Johnson 2HP outboards Service Manual, Page 14Get this manual
2-7 TROUBLE CHECK CHART
TROUBLE 1MOTOR WILL NOT START POSSIBLE CAUSE AFUEL SYSTEMSee Section Fuel shut-off valve not opened Fuel vent cap screw not open Speed control not advanced (throttle closed) Engine flooded Old fuel Clogged fuel filter Choke not closing completely Fuel system faulty BIGNITION SYSTEMSee Section Cam or linkage improperly adjusted Inverted breaker cam Sheared flywheel key Ignition system faulty APOWER HEADSee Section Carburetor and magneto not synchronized Air leak at manifold gasketswarped manifold (backfires) Broken leaf valves (backfires) Excessive carbon on pistons and cylinder head Stuck piston rings, or scored cylinder, or piston BCARBURETORSee Section Poor fuel mixtoo much lubricant (oil) Carburetor adjustment(too leanbackfires) (too richexcessive fuel) Choke not operating properly Air leaks at packing nuts or core plugs Inlet needle and seat worn or sticky Boss gasket damaged Incorrect carburetor float setting CFUEL TANKSee Section Faulty fuel line Fuel tank or filter plugged Fuel line restricted Fuel vent not open Fuel shut-off valve restricted DEXHAUST GAS ENTERING CARBURETORSee Section Exhaust cover screws leaking Cover plate gasket damaged Exhaust relief obstructed Lower bearing housing gasket leaking Cracked exhaust housing Lower bearing housing screws loose EOVERHEATING POWER HEADSee Section Exhaust cover gasket eaking Power head gasket improperly installed or damaged Head gasket eaking (warped cylinder head) (water in cylinder) FLOWER UNITSee Section Water intakes obstructed Pump cover air bleed restricted Water passages or tube obstructed Pump impeller damaged Pump cover worn Pump chamber in gearcase worn Water tube improperly installed GEXHAUST GASES ENTERING COOLING SYSTEM See Section Damaged water tube grommet or "0" ring Exhaust housing to lower motor cover gasket damaged