Replacing Boat Throttle Trim Switch: A Step-By-Step Guide

The trim switch on a boat throttle is a powerful tool that allows sailors to navigate through shallow water by tipping the engine up. It is also used to trim the motor down and tuck it underneath the boat when the throttle is hit, acting as a lever arm. This article will provide an overview of the replacement process for the trim switch on a boat throttle, including specific instructions for the Mercury Quicksilver trim switch.

Troubleshooting the trim switch

Firstly, before dismantling anything, it is important to test the trim switch and wiring. Perform a visual inspection by pulling back and forth on the wires while operating the switches. You can then test with a meter. At the commander switches, the red wire will always have 12 volts. The green wire gets 12 volts when the trim toggle is held down, and the blue wire gets 12 volts when the toggle is held up or the trailer switch is pushed in. The purple wire is part of the limit switch circuit.

If the switch voltages are as they should be, move on to the trim/tilt pump assembly. Ensure that the purple wire connector (single wire) and the blue wire connector with two blue wires are not corroded or loose. These wires are the trim position and limit switch wires. Pull them apart, inspect, and reconnect them if necessary.

Next, check the three-wire connector (red, blue, and green) at the pump assembly. This plug can vibrate loose and cause issues. Remove it, inspect for corrosion, and reconnect it if necessary.

If the issue persists, disconnect the trim/tilt assembly wires from the battery and check the nuts and studs on the solenoids for clean and tight fittings. Each solenoid has three wires and a buss bar connected to it. The bases will have a black ground wire and small blue and green wires.

On top of each solenoid, you will find a large copper stud. The large blue wire from the pump motor attaches to the solenoid with the small blue wire at the base, and the large green wire from the pump motor attaches to the solenoid with the small green wire at the base.

If the above steps do not resolve the issue, the trim limit switch may be out of adjustment. To adjust it, have someone hold the trim switch up while you measure the distance between the trim cylinder attaching bolts. Adjust the trim limit switch until the distance is 22 inches, and then tighten the screws.

If you are still experiencing problems, it may be necessary to replace the trim switch. This process can vary depending on the make and model of your boat throttle, so it is recommended to refer to the owner's manual or seek assistance from a qualified marine technician.

Testing the motor

Testing a boat motor can be done without a boat or ocean. Here are the steps to test a boat motor on land:

Mount the Motor

Mount the motor to a sturdy platform. Ensure that the platform is strong enough to support the weight of the motor to avoid any accidents.

Prepare the Bucket

Place a large bucket underneath the mounted motor. The bucket should be big enough to catch any potential spills or messes. Fill the bucket with water until the propeller is completely submerged. This step is crucial to properly testing the motor, as the propeller must be underwater to function correctly.

Prepare the Fuel

Clean out the gas can of any old fuel and oil mixture, as it may be contaminated with water. Then, add fresh fuel and the appropriate amount of two-stroke oil. Refer to the manufacturer's instructions for the correct oil-to-gas ratio, as this can vary between brands. For the best performance, consider using Red Line oil at a ratio of 8 ounces per gallon of gas.

Prime the Motor

If the motor hasn't been started in a while, you may need to use starting fluid to help it turn over. Remove the rubber shields covering the spark plugs, and unscrew the spark plugs completely. Spray starting fluid or ether into the spark plug cavities and the air filter.

Start the Motor

Attempt to start the motor by pulling the cord. If it doesn't start, you may need to jump-start it, similar to how you would jump-start a car. Use a battery of at least 12 volts and connect the jumper cables to the metal screw heads near the motor's starter.

Additional Tips

• It is crucial to ensure that the water level is high enough to submerge not just the propeller but also the impeller/water pump housing.
• Check the compression in each cylinder and look for consistent psi across all cylinders.
• Test the spark for each cylinder using a grounded "air gap" tester.
• Be cautious when performing this test, as improper water levels can damage the impeller and gearcase.
• Do not attempt high-speed operation during this test, as the water will become frothy, affecting propeller performance and engine breathing.

Removing the throttle lever

To remove the throttle lever, you will need to first identify the type of throttle control you have. In some cases, you may need to remove the entire throttle assembly from the boat to access the necessary components.

For standard throttle controls with a red grip, there is usually a screw on the backside of the lever and a small set screw on the hub that can be accessed through a small hole on the bottom of the assembly. Removing these screws will allow you to detach the lever from the pivot hub.

If you have a Quicksilver Commander 3000, the process is slightly different. First, push the throttle-only button in and push the throttle handle forward. You can then pull out the throttle-only button, possibly using a small screwdriver. Remove the nut inside, and the handle should come off. You can then unplug the handle from the panel. There is a lower Phillips-head screw near the bottom of the handle that needs to be removed to detach the release handle and spring. Under the release handle is another Phillips-head screw that, once removed, will allow you to separate the two halves of the handle and access the trim switch.

In some cases, you may need to remove the whole unit from the bulkhead, which is secured by three bolts from the outside and three nuts inside. With the control lever in the neutral position, undo the central bolt to pull off the arm. The red neutral-lock lever is held by a small bracket and two screws, and it may also have a spring fitted behind it, so take care when removing it.

Once you have removed the throttle lever, you can proceed to replace the trim switch.

Disassembling the control handle

First, identify the type of control handle you have. In the case of a Quicksilver Commander 3000, the disassembly process is as follows: push the throttle-only button and then push the throttle handle forward. You can then use a small screwdriver to gently pry out the throttle-only button. Remove the nut inside, which holds the handle in place. Now, move the control lever back to the neutral position, as it will make reassembly easier. At this point, you can unplug the handle from the panel.

Next, locate and remove the lower Phillips-head screw near the bottom of the handle to detach the release handle and spring. There should be another Phillips-head screw underneath the release handle; remove this as well. This will allow you to separate the two halves of the handle and access the internal components.

For other types of control handles, the process may vary slightly. In the case of the Quicksilver Commander 2000, the steps are as follows: put the control in the full forward position. Pry out the button at the pivot point of the handle. You should then be able to see a nut that holds the handle in place. Remove this nut. Before proceeding, move the control lever back to the neutral position to make reassembly easier.

Now, you will need to remove the whole unit from the bulkhead. It is secured by three bolts on the outside and three nuts on the inside. With the control lever in the neutral position, undo the large central bolt. This will allow you to pull off the arm, but it will still be connected by the trim switch cable.

The red neutral-lock lever is held by a small bracket and two screws, and it also has a spring fitted behind it, so take care when removing it. Removing this will give you access to the trim switch. You may also need to take off the lower unit cover, which is usually held by two screws, to get better access to the wiring.

Once you have disassembled the control handle and accessed the trim switch, you can proceed to replace it with a new one. Make sure to follow the correct wiring connections and secure the new switch in place. Finally, reassemble the control handle by following the above steps in reverse.

Replacing the trim switch

The trim switch on a boat throttle can be replaced by following these steps:

First, ensure that the problem is with the switch. In many cases, issues with the trim function may be caused by a faulty trim limit switch or wiring rather than the switch itself. Check if the "trailer" switch is working. If it is, you can bypass the trim limit switch to test the trim switch. Locate the two black wires coming through the transom, one connected to a purple/white wire and the other to two blue/white wires. Jumper between the two connectors and then try the trim switch. If it works, the issue is likely with the trim limit switch or wiring, not the trim switch.

If the trim switch is indeed faulty and needs to be replaced, the process will depend on the specific model of your throttle control. For a Quicksilver Commander 3000:

• Push the throttle-only button and move the throttle handle forward.
• Pry out the throttle-only button using a small screwdriver if necessary.
• Remove the 11/16 nut that holds the handle in place.
• Move the control lever back to the neutral position to make reassembly easier.
• To separate the two halves of the handle, remove the lower Phillips head screw near the bottom of the handle, which will also remove the release handle and spring.
• Under the release handle, there is another Phillips head screw that needs to be removed to access the trim switch.

For other models, such as the Quicksilver Commander 2000, the process may be slightly different:

• Remove the entire unit from the bulkhead by unscrewing the three bolts from the outside and the three nuts inside.
• With the control lever in the neutral position, remove the large central bolt. This will allow you to pull off the arm, but it will still be connected by the trim switch cable.
• Remove the red neutral-lock lever by unscrewing the two screws that hold it in place. Be careful, as there may also be a spring fitted behind it.
• You may also need to remove the lower unit cover to access the wiring and trim switch.

Once you have accessed the trim switch, you can replace it with a new one. Make sure to get the correct replacement switch for your specific model. After replacing the switch, follow the disassembly steps in reverse to reassemble the throttle control.

It is important to note that some issues with the trim function may be caused by corrosion or loose connections, so it is recommended to check and clean the connectors before assuming the switch is faulty. Additionally, refer to the manual or seek professional assistance if you are unsure about any of the steps or if your model is different from the ones mentioned above.

Frequently asked questions