1997 Johnson/Evinrude EU 25, 35 HP 3-Cylinder outboards Service Manual, Page 225Get this manual
Starter System Voltage Drop Test By making systematic check of the starter system, any component or electrical connection having excessive resistance can be located&
Avoid accidental starting of engine while servicing; twist and remove all spark plug leads
Clean and retighten, or replace, any connection, cable, or component having greater than specified voltage drop
1Connect voltmeter positive lead to battery positive postConnect voltmeter negative lead to starter solenoid positive terminalTurn key switch to START to crank engineVoltage reading should not exceed 0.3 voltStep 2, connect the voltmeter leads only while the engine is cranking, or damage to the voltmeter can occur2Connect voltmeter negative lead to the starter side of the starter solenoid terminalWhile cranking engine, connect voltmeter positive lead to starter solenoid opposite terminalVoltage reading should not exceed 0.2 voltRemove voltmeter positive lead from starter solenoid and stop cranking engine