Maintenance; Troubleshooting Guide; Important Information; Troubleshooting Chart - Mercury MerCruiser Service Manual

Compact Hydraulic Steering
2. While maintaining pressure, check all port fittings and hose connections. Ensure that there are no leaks. If leaks are
present, correct them before proceeding.
3. Turn steering wheel (any wheel on multi‑steering station) very hard to starboard to pressurize system.
4. While maintaining system pressure, check all starboard fittings and hose connections. Ensure that there are no leaks. If
leaks are present, correct them before proceeding.
NOTE: A significant drop in fluid level at the helm while performing the system check may indicate there is air in the
system. Further filling and purging is required.
5. If no leaks are present, the system is ready for service.

Maintenance

Proper installation and maintenance is essential for the steering system to function. Use only the recommended hardware
when installing the steering system. Follow all installation specifications and recommended maintenance procedures.
IMPORTANT: Loss of hydraulic fluid or hydraulic pressure may cause the steering system to malfunction. Ensure that the
steering system maintains the proper level of hydraulic fluid.
NOTE: A damaged cylinder shaft can cause seal failure and leaks. Replacing seals on a damaged cylinder assembly will not
stop leaks. A damaged cylinder shaft must be replaced immediately.
Check the hydraulic fluid level in the helm pump.
Check for leaks.
Check mechanical linkages and connections. Tighten loose
parts and replace badly worn parts.
Check the cylinder shaft for nicks and scratches.

Troubleshooting Guide

Important Information

When troubleshooting requires component removal from the vessel or the dismantling of steering system components, this
work must be carried out by a qualified marine mechanic. The following is offered as a guide only, and neither Mercury
MerCruiser nor the helm manufacturer are responsible for any consequences resulting from incorrect repairs.
Most faults occur when the installation instructions are not followed and usually show up immediately upon filling the system.
The following troubleshooting chart provides the most common faults encountered and their likely cause and solution.
Sometimes when returning the steering wheel from a hard‑over position, a slight resistance may be felt and a clicking noise
may be heard. This should not be mistaken as a fault, as it is a completely normal situation caused by the releasing of the
lockspool in the system.
Fuel vapors trapped in the engine compartment may be an irritant, cause difficulty breathing, or may ignite resulting in a fire
or explosion. Always ventilate the engine compartment before servicing the power package.

Troubleshooting Chart

Symptom
1. During filling, the helm becomes
completely jammed.
2. System is difficult to fill. Air escapes
from the top of the helm even after the
system appears full.
Page 8B-10
!
Task
!
Cause
Blockage in the line between
the helms and the cylinders.
Air in system.
© 2016 Mercury Marine
WARNING
Two times per year, or at the first indication that the steering
system is not operating correctly, whichever occurs first.
WARNING
Ensure that hoses were not kinked or pinched during
installation. If so, the hose must be removed and
replaced.
Review filling instructions.
Interval
Solution
90-8M0099748 eng DECEMBER 2015