Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-42794--1, Page 213Get this manual
Troubleshooting Determining if Problem is Electrical or Hydraulic
When problem is encountered with the Power Trim systemthe first step is to determine whether the malfunction is in the "electrical systemor the "hydraulic system Refer to the following chart to determine which system is at fault
Trouble Chart
Engine will not trim up or down
tDetermine if Power Trim pump motor operates when appropriate trim circuit is activated
Engine trims up, will not trim down
Engine trims down, will not trim upPump motor operates