Mercury Mariner Outboard 225 3 Litre Service Manual 1994, Page 208Get this manual
Motor and Electrical Tests Repair Trim Pump Motor Test;
Motor Disassembly
1Remove screws and clamp
Do not perform this test near flammable materials, as spark may occur while making electrical connections1Connect 12 volt power supply to motor wires [positive (+) to blue wire) and negative (-) to black wire]Molor should runDisconnect blue wire and connect green wire to positive (+) terminal of power supplyMotor should runIf motor does not run, disassemble and check components
Solenoid Test
Do not perform this test near flammable materials, as spark may occur while making electrical connections1Disconnect all wires from solenoid termi nalsleads to solenoid terminals and 23Connect 12 volt power supply to terminals and Solenoid should click and meter should read zero (0) ohms (fun continuity)