Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-42794--1, Page 193Get this manual
Troubleshooting the "Down" Circuit (When "Up" Circuit is OK) Connect Voltmeter red lead to Point and black lead to Point 2Depress the "Down" trim button Battery voltage should be indicated Battery Voltage Indicated: Connect Voltmeter red lead to Point 9Voltage should be indicatedNo Voltage IndicatedConnect Voltmeter black lead to Point 3Depress "Down" trim button If battery voltage is indicated" Downsolenoid black ground wire is open
Battery Voltage Indicated: Check "Down" solenoid terminals for loose or corroded connections Test "Down" solenoidRefer to "Testing SolenoidFuseand Trim Pump Motor