Troubleshooting Outboard Boat Tilting At Wide Open Throttle

Outboard boat engines are designed to run at high RPMs, including extended periods of wide-open throttle without harming the engine. However, issues with the tilt and trim unit can cause problems with the engine's performance. The tilt and trim unit allows you to adjust the angle of the engine, optimising the boat's performance under a wide variety of conditions. Troubleshooting tips include checking the battery, listening for the solenoid/start relay, and testing the motor. In some cases, the problem may lie with the hydraulic pump assembly, which can cause the engine to slip down when in the raised position or not stay trimmed.

Troubleshooting an outboard motor that tilts down but not up

Visual Inspection of the Hydraulic System:

• Check for any leaks in the hoses or cylinders. Leaks can cause a loss of pressure, preventing the outboard motor from tilting up.
• Inspect the fluid levels in the hydraulic reservoir. A low fluid level can cause the motor to tilt down but not up. Ensure the reservoir is filled to the correct level.

Testing the Electrical System:

• Verify the battery voltage. A weak battery may prevent the solenoids from activating properly.
• Examine the wiring connections for corrosion or damage. Corroded or damaged connections can lead to a loss of electrical power.
• Test the trim switch for continuity. A faulty switch can prevent the solenoids from functioning correctly.

Inspecting Solenoid Valves and Wiring:

• Check the solenoid valves for any signs of damage or wear. Damaged valves may restrict the flow of hydraulic fluid.
• Inspect the solenoid wiring for any damage or corrosion. Issues with the wiring can prevent the solenoids from activating properly.

Disassembling the Hydraulic Pump for Closer Inspection:

• If the above steps do not identify the issue, you may need to remove the hydraulic pump for further inspection.
• Disconnect the hydraulic lines from the pump and remove it from the boat.
• Disassemble the pump and carefully inspect the internal components for any damage or wear.

Replacing Damaged Parts:

• If you find any damaged parts during your inspection, they will need to be replaced with high-quality replacements.
• Follow the manufacturer's instructions for proper installation.
• After replacing parts, test the outboard motor's tilt function to ensure it is working correctly.

Additional Considerations:

• Check the three-wire connector (red, blue, and green) at the pump assembly. This connection can sometimes vibrate loose, causing issues. Clean the pins if necessary and reconnect securely.
• Inspect the solenoids on the trim pump. The blue wire solenoid is for raising the motor. You can test it by jumping the two top studs; if the pump raises the motor, replace the solenoid.
• Check the trim/tilt switch and the outboard trim limit switch. The trim/tilt switch should show continuity only when toggled in each direction between two wires. The outboard trim limit switch will only activate if the outboard limit switch is below the adjusted trim limit.
• Examine the trim motor. If it does not turn, there may be internal motor issues. If it turns, the down button may be corroded.
• Locate the manual tilt release valve, typically a small knob on the bracket housing the trim motor. You can loosen this valve to manually adjust the motor position in case of power failure or a faulty switch.
• Check for any leaks in the hydraulic system. If the motor tilts all the way up, wipe it down and identify the source of any leaks. Leaks at the seals or around the piston assembly indicate a potential issue with the seals.

Electrical or tilt/trim motor issues

If you try to adjust the engine and nothing happens, the first step is to check that your battery is charged and that the battery switch is in the “on” position. Listen for the solenoid/start relay while operating the control (tilt) switch up or down. If you hear nothing, the problem is likely with the tilt switch, solenoid, or with the wires or connections between the two.

If you hear a slight clicking noise while pressing the tilt switch, then you have power from the control switch to the solenoid or relay. Next, check the operation of the power tilt and trim motor itself. All tilt/trim systems use a 12-volt DC reversing-type motor that has one green wire and one blue power wire. If you’re dealing with an older system, the motor may also have a third, black wire, which is used to provide ground to motors that don’t receive it through their casing. Applying power to the blue wire raises the engine, while energizing the green wire lowers it.

To test the motor, first disconnect the blue and green wires. Remove the quick-disconnect plug between the motor and solenoid or detach the two wires where they connect to the solenoid or relay. Once disconnected, use a jumper wire to apply 12 volts DC directly to the appropriate wire. If the engine is in the down position, energize the blue wire. If the engine is in the raised position, connect the jumper to the green wire to lower it. If the motor fails to operate with power applied directly to the blue or green wire, the issue is with the motor. If the motor operates, then the problem is a lack of power to the motor (faulty solenoid or relay, bad connections, etc.).

Failed solenoids, relays, and corrosion (at connections, relay sockets, quick-disconnect plugs, etc.) are some of the most common problems associated with tilt and trim system failure.

Hydraulic pump assembly problems

If the tilt and trim motor is working, but the engine won't raise or lower, slips down when raised, or won't stay trimmed, the problem is likely with the hydraulic pump or valve body assembly.

First, check the hydraulic fluid reservoir level. If the level is adequate, the problem is likely with the hydraulic pump. A low fluid level could indicate a leak at the seals, as could visual fluid around the piston assembly. Repairs at this point usually involve removing and rebuilding the pump or replacing it at a qualified repair facility.

Before any physical tests are administered, there are several basic visual tests to conduct to ascertain the state of the pump. Check that the electric motor is running and that the pump shaft is rotating. Check the oil level, which should be three inches above the pump suction to avoid a vortex forming in the reservoir and allowing air into the pump. If the oil level is low, determine where the leak is in the system.

If the pump is making a high-pitched whining sound, it is likely cavitating. If it has a knocking sound, aeration is the probable cause. Cavitation is the formation and collapse of air cavities in the liquid, which occurs when the pump cannot get the total volume of oil it needs. Aeration is when outside air enters the pump's suction line.

Water damage to the trim/tilt switch

If the trim/tilt switch has been compromised by water damage, it may need to be replaced. This is a relatively inexpensive part to replace, and doing so can help prevent further issues with the boat's motor.

To diagnose a faulty trim/tilt switch, you can perform the following steps:

• Check that the battery is charged and the battery switch is in the "on" position.
• Listen for the solenoid/start relay while operating the control (tilt) switch up or down. If you don't hear anything, the problem may be with the tilt switch, solenoid, or the wires/connections.
• Check for a blown fuse.
• If you hear a slight clicking noise while pressing the tilt switch, there is power from the control switch to the solenoid or relay.
• Disconnect the blue and green wires from the power tilt and trim motor to test it.
• If the motor fails to operate with direct power applied to the blue or green wire, the issue is with the motor itself.
• If the motor operates, the problem is likely a lack of power to the motor, possibly due to a faulty solenoid or relay, or bad connections.

By following these steps, you can identify whether the issue lies with the trim/tilt switch, the motor, or another component of the tilt and trim system.

Faulty solenoid or relay

If your outboard boat is tilting at wide open, it could be due to a faulty solenoid or relay. The solenoid and relay are crucial components in the tilt and trim system, which allows you to adjust the angle of the engine to optimise the performance of your boat. Here are some detailed information and instructions to help you troubleshoot and address the issue:

Troubleshooting Steps:

• Identify the Problem: Determine whether the issue lies with the electric tilt/trim motor or the hydraulic pump assembly. This can be done by trying to raise or lower the engine. If nothing happens, start by checking the battery to ensure it is charged and the battery switch is turned on.
• Listen for the Solenoid/Relay: Operate the control (tilt) switch up or down and listen carefully. If you don't hear anything, the problem is likely with the tilt switch, solenoid, or the wires/connections between them. A slight clicking noise while pressing the tilt switch indicates power is reaching the solenoid or relay.
• Test the Power Tilt and Trim Motor: All tilt/trim systems use a 12-volt DC reversing-type motor with specific coloured wires. By applying power to these wires, you can test the motor's function. Disconnect the wires and use a jumper wire to apply 12 volts DC directly to the appropriate wire, depending on the desired direction of the engine (up or down).
• Isolate the Issue: If the motor fails to operate with direct power, the issue lies with the motor itself. However, if the motor operates, the problem is likely a lack of power to the motor, indicating a faulty solenoid or relay, bad connections, or corrosion.

Further Instructions:

• Solenoid and Relay Replacement: If you determine that the solenoid or relay is faulty, you may need to replace them. This can be done by purchasing the appropriate replacement parts and following the installation instructions provided by the manufacturer.
• Connection Inspection: Check all connections for any signs of corrosion or damage. Ensure that all wires are securely connected.
• Hydraulic Pump Assembly: If the tilt and trim motor is functional, but the engine won't raise or lower, the issue may lie with the hydraulic pump or valve body assembly. Check the hydraulic fluid reservoir level and look for any signs of leaks or damage.
• Corrosion and Damage: Pay close attention to corrosion or damage at connections, relay sockets, and quick-disconnect plugs, as these are common issues associated with tilt and trim system failures.
• Professional Assistance: If you are unsure about any part of the troubleshooting or repair process, it is always best to consult a qualified marine technician or repair facility for guidance or assistance.

Frequently asked questions