2009 Yamaha F40 Outboard Service Manual, Page 82Get this manual
YDISTroubleshooting the power unit
Troubleshooting the power unit
Troubleshooting procedure
1Before troubleshooting the outboard motor, make sure that fresh fuel of the specified type has been used2Make sure that all electrical connections are secure and free from corrosion, and that the battery is fully charged3Check the trouble code using the YDIS first, and then check the electronic control system following the trouble code chart4When trouble code is detected, check the data logger of the engine ECM record data graph as well5If trouble code is not detected, check as well the power unit according to "Troubleshooting the power unit (trouble code not detected)" (4-9)6Before using the YDIS to check the power unit, check the engine ECM circuitSee "Checking the engine ECM circuit" (5-16)