2005 Yamaha F90TR 90HP Outboards Factory Service Manual, Page 220Get this manual
TRBL SHTG
Troubleshooting
NOTE: Check that all electrical connections are tight and free from corrosion, and that the battery is fully charged to 12 To diagnose mechanical malfunction, use the troubleshooting charts pertaining to the trouble located in this chapterAlso, when checking and maintaining the outboard motor, see Chapters for safe maintenance procedures To diagnose malfunctioning sensor or switch, use the diagnostic test lead to determine the cause
Power unit
Symptom: Engine does not crank Check the starting system Check the power unitCheck that the gearshift is in the neutral position