2007-2009 Yamaha F15/F20 Outboard Service Manual, Page 267Get this manual
TRBL SHTG
Troubleshooting
Symptom 1: Engine does not start (engine cranks) Symptom Spark plug does not spark Cause Spark plug malfunction Spark plug cap malfunction Ignition coil malfunction Engine stop lanyard switch malfunction Charge coil malfunction Pulser coil malfunction CDI unit malfunction Fuel not supplied Pinched or kinked fuel hose Clogged fuel filter Fuel pump malfunction Carburetor malfunction Prime Start malfunction Low compression pressure Valve clearance not adjusted correctly Damaged cylinder head gasket Damaged valve Valve stuck to valve guide Scratched piston Cause Malfunction of the carburetor internal parts Checking step Check the spark plugCheck the spark plug capCheck the ignition coilCheck the engine stop lanyard switchCheck the charge coilCheck the pulser coilCheck the CDI unitCheck the fuel hoses and fuel hose jointClean or replace the fuel filterDisassemble and check the fuel pumpDisassemble and check the carburetorCheck the Prime StartAdjust the valve clearanceDisassemble and check the cylinder head and power unitRefer to page 3-5 8-22 8-22 8-24