Replacing Boat Throttle Control: A Step-By-Step Guide (2025)

If you're experiencing issues with your boat's throttle control, such as stiff controls or levers that move too far, it's likely that you'll need to replace the control cable. To do this, you'll first need to identify the type of engine and control head your boat has. There are two types of control cables: OEM-specific and Universal. Once you've identified the correct type of cable, you can measure the length of the cable you need by examining the plastic jacket on the cable. When installing a new throttle control, you'll need to take three measurements to ensure you have the correct length of control cables.

Identifying the type of engine and control head

To replace your boat's throttle control, you need to identify the type of engine and control head on your boat. This is important because it determines the type of control cable you need. There are two types of control cables: OEM-specific and Universal.

OEM-specific control cables have end fittings designed specifically for your engine and control head. For instance, if you have a Mercury outboard engine, you would need a control cable with the appropriate end fittings for that specific engine. Other examples of engines that use OEM-specific control cables include Volvo, Suzuki, and Yamaha.

On the other hand, Universal control cables come with threaded ends. To use a Universal control cable, you need to match it with the appropriate connection kit, which needs to be specific to your engine and control head.

To determine the length of the control cable you need, you can examine the plastic jacket on the cable. For a Telefax cable, the model number will indicate the cable length in feet. For a Morse Cable, the length is indicated in inches. It's important to note that some OEM cables on boats may be in half-foot increments, but replacement cables are typically available in full one-foot increments. Therefore, it's recommended to measure the cable from tip to tip and round up to the nearest foot when choosing a replacement.

Additionally, when installing a new throttle control, you need to take three critical measurements to ensure you get the correct length for the control cables. The first measurement is from the control, along the gunnel, to the point where the gunnel and transom meet. The second measurement is from the intersection of the gunnel and transom to the centerline of the engine. The third and final measurement is from the centerline of the engine to the throttle attachment point, as well as the shift attachment point. By following these steps and measurements, you can accurately identify the type of engine and control head, as well as select the appropriate control cable for your boat's throttle control replacement.

Choosing the right control cable

When choosing the right control cable for your boat, there are several factors to consider. Firstly, it is critical to order the correct length of cable. The cable should be long enough to reach from the throttle and shift controls to the engine, but not excessively long. If you are replacing an existing cable, use the same length as the one you are removing. The length is usually stamped on the jacket of the cable, typically near the helm end. If the size is not visible on the old cable, you can measure it from tip to tip and then round up to the nearest foot when ordering a new one.

It is also important to select the appropriate type of cable for your engine and control head. There are two main types of control cables: OEM-specific and Universal. OEM-specific cables have end fittings that are designed specifically for your engine and control head. Universal cables, on the other hand, come with threaded ends and require a connection kit that matches your engine and control head.

When choosing a control cable, you should also consider the brand and grade. Reputable brands such as Dometic Marine (formerly SeaStar) and Uflex offer both standard and premium cables. Premium cables, such as Dometic's Xtreme series and Uflex's Mach series, offer several advantages over standard cables. They provide smoother control, tighter bending capabilities, and improved precision in shifting and throttle control. While premium cables are more expensive, they can enhance the performance and longevity of your boat's throttle and shift functions.

Additionally, it is recommended to replace both the throttle and shift cables simultaneously. This ensures optimal performance and prevents potential issues that may arise if only one cable is replaced. By considering factors such as length, type, brand, and grade, you can choose the right control cable for your boat's throttle control system.

Measuring the control cable

Identifying the Cable Type

Before measuring, it's important to identify the type of control cable you have. There are two main types: the Original Equipment Manufacturer (OEM) specific cable and the Universal control cable. The OEM cable will have end fittings specific to your engine and control head, while the Universal cable will have threaded ends that require a connection kit. Knowing which type you have will help you determine the correct replacement.

Measuring for a New Installation

If you're installing a new control cable, follow these steps:

• Measure the distance from the control head to the clutch or throttle connection. This is known as the A + B distance.
• Ensure that the path is a straight line and unobstructed.
• Round off the total A + B distance to the nearest whole foot to get your cable length.
• For outboard engine installations, add an extra three to four feet to the obtained length to allow for engine movement.

Measuring for a Replacement Cable

If you're simply replacing an existing cable, the process is slightly different:

• Measure the cable from tip to tip.
• Round off the measurement to the nearest whole foot.
• Specify the cable length in feet when ordering a replacement.

Reading the Cable Jacket

To make things easier, you can also check the cable jacket for length information. For example, on a Teleflex cable, the model number will indicate the cable length in feet. On a Morse Cable, the last three digits will represent the length in inches. Keep in mind that some OEM cables are measured in half-foot increments, while replacement cables are usually available in full-foot increments.

Additional Considerations

When measuring control cables, it's important to maintain a minimum bend radius of about 8 inches (200 mm) for optimal performance. Additionally, if you're replacing both the throttle and shift cables, it's recommended to replace them simultaneously, as one failing cable could indicate that the other is not far behind.

Installing the new shift and throttle control

To install a new shift and throttle control, you will need to know the correct length for the control cables. This will require three measurements.

First, measure from the control, back along the gunnel, to the point where the gunnel and the transom meet. Second, measure from the intersection of the gunnel and the transom, across to the centre line of the engine. Third, measure from the centre line of the engine to the point where the throttle attachment occurs, as well as the shift attachment.

When measuring control cables for outboard applications, add four feet to the above dimensions. This provides plenty of cable for the engine to move back and forth.

If you are installing a new OEM cable, it will have the appropriate end fittings for your specific engine and control head. For example, it may be designed for a Mercury outboard, a Volvo engine, a Suzuki, or a Yamaha.

On the other hand, if you are installing a Universal type of control cable, it will come with threaded ends. To use this cable, you will need to match it with the appropriate connection kit, specific to your engine and control head.

To determine the exact replacement length for a Teleflex cable, look at the plastic jacket on the cable itself. The last two digits in the model number will represent the cable length in feet. For a Morse Cable, the length will be given in the last three digits, in inches.

Some cables on boats will be in half-foot increments, but replacement cables are usually only available in full one-foot increments. Therefore, take the cable, measure it tip-to-tip, and then round up to the nearest foot. That will be the replacement cable length you need.

Testing and troubleshooting

Before you begin testing and troubleshooting your boat's throttle control, ensure that you have the necessary tools and safety equipment. It is recommended that you wear protective gear, such as gloves and eye protection, when working on your boat's throttle control system.

Firstly, you should inspect the throttle control for any visible signs of damage or corrosion. Look for any loose connections, broken wires, or wear and tear on the throttle cable. If you notice any issues, replace the affected parts. Regular maintenance and inspection of the throttle control can help prevent major problems and ensure the safety of your boat.

To test the throttle control, start by checking the safety features. Ensure that the neutral safety switch is functioning properly. With the motor in neutral and the throttle closed, adjust the controls and cables. The shift cable should be in the mid-position, and the throttle cable should be at the end of its throw. Check if the safety switch is depressed, allowing the starter to work.

Next, identify the throttle cable by moving one of the cables while observing the engine. The throttle cable will be connected to the carburettor or fuel injection system, and when moved, it should cause the carb or fuel injection to respond. If you adjust the other cable, the shift plate should move.

When testing the throttle control, pay attention to the engine's response. Listen for any unusual noises, and observe the engine's performance. If you notice any sticking or loose cables, have them repaired immediately to prevent further damage. Ensure that the throttle responds smoothly and precisely to your inputs.

Finally, test the throttle at regular intervals and note any deficiencies. This will help you identify any developing issues and address them promptly. Keep a record of your testing results, and if you notice any significant changes or degradation in performance, consult a professional for further guidance.

Frequently asked questions