Cylinder/Helm Pump Check - Dometic HC4645H Troubleshooting Manual

EN

6.3 Cylinder/helm pump check

• Center engine
• Trim engine UP
• Turn steering wheel 1 turn to the starboard side
• Let go of wheel
• Let engine fall over to the side
• While the engine is falling, watch the steering wheel (place a piece
of tape on the wheel)
• Repeat the above turning to the port side
Results
• If at any time the steering wheel turns "on its own" then the helm pump is
at fault and will have to be replaced.
• If the engine falls to "one side only", then the helm pump (or autopilot) is
at fault.
• If the engine falls over all the way to one side only then further testing is
required. See below for further testing. If engine falls over only partially
then air is in the system.
• If the engine falls to both directions quickly, then the cylinder (or
autopilot) is at fault and will need to be replaced. See further testing.
• Remove autopilot from the system and repeat the tests. If problem stops,
replace autopilot. If problem continues replace helm/cylinder.
Further testing
• Assuming system is free of air remove hoses from fittings on the cylinder.
Quickly cap off fittings on cylinder with p/n HF5524.
• Try and push engine from side to side in both directions.
• If you are able to push engine in one or both direction all the way the
cylinder is at fault and must be repaired or replaced.
• If the cylinder "locks up" in both directions replace or repair the helm.
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