Mercury 100 FourStroke, Service Manual

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5B-6 - MID-SECTION 90-830234R3 DECEMBER 1997
Troubleshooting
Determining if Problem is Electrical
or Hydraulic
When a problem is encountered with the Power Trim
system, the first step is to determine whether the mal-
function is in the “electrical system” or the “hydraulic
system.” Refer to the following chart to determine
which system is at fault.
Problem Chart
Outboard will not trim up or down.
Outboard trims up, will not trim
down.
Outboard trims down, will not trim
up.
Outboard will not return completely
to “down” position or returns part
way with jerky motion.
Outboard thumps when shifted.
Outboard trails out when backing off
throttle at high speed.
Outboard will not hold a trimmed po-
sition or will not remain tilted for any
extended period
Outboard will not hold trim position
when in reverse.
Determine if Power Trim pump mo-
tor operates when appropriate trim
circuit is activated.
Pump motor operates.
Refer to “Hydraulic System
Troubleshooting.” Refer to “Electrical System
Troubleshooting.”
Pump motor does not oper-
ate.