Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 342Get this manual
POWER TRIM
Motor and Electrical TestsRepair
Trim Pump Motor Test
WARNING
Do not perform this test near flammable materials, as spark may occur while making electrical connections1Connect 12 volt power supply to motor wires; one motor lead to POSITIVE (+) battery terminal and the other motor lead to the NEGATIVE () battery terminalMotor should runReverse motor leads between battery terminalsMotor should run