Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-42794--1, Page 242Get this manual
Solenoid Test AWARNING
Do not perform this test near flammables (or explosives), as spark may occur when making connections1Disconnect all wires from solenoid terminals2Use an Ohmmeter (Rx1 scale) and connect meter leads between solenoid terminals and 23Connect 12-volt supply between solenoid terminals and 4Solenoid should click and meter should read zero ohms (full continuity)
TEST for GROUND Use an Ohmmeter (Rx1 scale) Place one lead of Ohmmeter on armature shaft and other lead on commutator, as shownIf continuity is indicated, armature is grounded and must be replaced