2009 Yamaha F40 Outboard Service Manual, Page 114Get this manual
ELEC Electrical system 10Connect the water detection switch coupler a
Checking the fuel injector
1Check the fuel injector operation using the YDIS "Stationary test" and check the operating sound2Disconnect the fuel injector couplers a
Float position B
Terminal c
3Turn the engine start switch to "ON," and then measure the input voltage between the fuel injector coupler terminal and the ground