Mercury Outboard Rigging, Steering, Gauges, and Throttle Controls

Mercury Marine Engine Rigging, Steering, Gauges, and Throttle Controls Resources and Information

Mercury gauges and throttle controls allow you to monitor your outboard engine performance with absolute precision and control. Need help getting your Mercury outboard motor up and running? Check out our blog entry on DIY Mercury outboard modification. We also offer harnesses to replace or repair your electric wiring.

We also regularly publish helpful resources to help you maintain your Mercury outboard motor, such as:

• Mercury Outboard Service Schedule
• Mercury Outboard Specs & Capacities Chart
• Mercury Outboard Serial Number Lookup

Mercury Outboard Rigging, Steering, Gauges, and Throttle Controls FAQs

How does Mercury’s outboard steering work?

Mercury offers several outboard steering system to match your boating needs. The main two are mechanical and hydraulic. 

Mechanical is the traditional boating steering system. This system uses a cable to connect the helm and steering wheel to the engine. This steering system is available with a “no-torque” option, which locks the wheel in position if you happen to remove your hands for added safety and control.

We’ve found that the preferred Mercury outboard steering system for larger boats with larger engines in hydraulic. This system uses a series of valves, hoses and hydraulic fluid to move the boat in the desired direction. This system also makes steering easier, more controlled and more comfortable for the pilot. Different sizes and styles of hydraulic systems are available, based on the boat size, the size and number of engines, pilot preferences and speed and performance requirements - from fishing to cruising to high-speed racing.

How do I select the right parts for my Mercury outboard motor?

PartsVu’s Mercury Outboard Maintenance Parts Library is the perfect reference when you need to replace common parts. That’s because these parts charts make it simple to find the right parts for your particular engine to perform regularly-scheduled maintenance. 

For Mercury outboard motors, perform maintenance after 100 hours of service or one year of operation (whichever comes first). More extensive service is recommended after 300 hours of service or three years.

After this period, maintenance is often more regular as the engine ages and parts wear out. For example, 1,000 hours generally requires an in-depth assessment by a qualified mechanic. Also, if you’re usually running your Mercury outboard in a more demanding manner, the manufacturer recommends more frequent servicing.

The following maintenance parts charts are organized by each model number for Mercury’s line of outboard engines.

Will doing maintenance void my Mercury outboard engine warranty?

Any warranty work done on your engine needs to be done by an authorized Mercury dealer. Your dealer will perform the work on your engine and file the claim with Mercury for you.

Your Mecury’s warranty does not apply to damage or failures caused by use of an accessory or part not manufactured or sold by Mercury. See the appropriate Mercury or MerCruiser warranty policy for your product or in your Operation, Maintenance & Warranty manual. In other words, if you modify your engine with non-Mercury parts and those parts cause damage, you will likely have a problem.

Fuels containing up to 10 percent ethanol are considered acceptable for use in Mercury engines. Fuels containing higher levels of ethanol are not considered acceptable for use, and can void the warranty.

Using the serial number of your engine, your local authorized Mercury dealer can quickly check your warranty coverage. They can verify that your engine is registered with Mercury, whether it is covered by Mercury’s standard factory warranty, if there is any additional promotional coverage, or if it is covered by a Mercury Product Protection plan.

How do I protect my Mercury outboard motor?

Cover it with Corrosion Guard. This rust inhibitor forms a water-resistant barrier on both painted and unpainted surfaces. We recommend using it at every service interval with a liberal application to all metal engine surfaces. You can also use it on outdrives, lower units, and power trim motors.

The marine environment is one of the harshest on the planet. This is why protecting your boat from corrosion is extremely important. For premium defense against rust, we highly recommend this product.

In order to maximize your engine’s performance, use this complete fuel treatment at every fill-up with any grade of gasoline. Quickare is an excellent defense against the problems associated with ethanol-blended fuels, including its corrosive effects on metals as well as the gum and varnish that result from fuel oxidation. See PartsVu’s Knowledge Center for our article on the problems of ethanol gasoline.

This product can also be used to clean up existing deposits in untreated fuel lines, tanks, carburetors, injectors, intake valves, and spark plugs. It will keep your fuel fresh for up to three months and can be used in all 2 and 4 cycle carbureted and fuel-injected gasoline engines. Use one ounce to treat every 10 gallons of fuel.

How do I flush my Mercury outboard engine?

It’s important to thoroughly flush your engine to remove any salt buildup if you are a saltwater boater, or general mud and grime if you are a freshwater boater. Failure to remove this debris can cause or contribute to corrosion in the engine. If you’re a saltwater boater, salt crystals in the lower unit can cause a great deal of damage.

Flush with the Engine Not Running (using a hose port)

You’ll need:

• Garden hose
• Water supply

If your engine has a hose adapter, simply screw the hose into the port, turn on the water and let the water run for about 5 minutes.

Finally, tilt the engine all the way up, then trim it all of the way down to make sure every drop of water drains from the engine.

**Caution** Do not run the engine when flushing while using a hose port. This method is solely designed for flushing while your engine is entirely off.

How do I change my Mercury outboard engine lower unit oil?

You’ll need:

• Sufficient quantity of lower unit oil / gear lube oil
• Oil pump 
• Drain pan
• Large flat head screwdriver
• A few rags

We strongly recommend changing your Mercury outboard lower unit oil before storage to make sure there is no water in the lower unit’s oil. Any water in the oil could freeze, expand, and crack your lower unit. Also, changing lower unit oil means one less thing to do at the beginning of next season.

First, you’ll need to know how much lower unit oil / gear lube you need to fill your lower unit – check your owner’s manual. 

Locate the lower and upper lower unit oil drain holes. With your drain pan in position, first, remove the lower drain screw. The oil will start to drip out into the drain pan.

Next, remove the upper drain screw—oil will drain out quickly. Allow the oil to drain completely.

It is essential that you pay close attention to your lower unit’s oil. If the oil is a milky color, there is water in the lower unit, and you will have significant problems down the road. If this is the case, go directly to your marine mechanic to diagnose the problem and hopefully fix the issue before it causes more damage.

With the oil completely drained, screw in your pump fitting and attach the pump. Remove the cap of your bottle of lower unit oil and screw the pump onto the bottle. 

Pump until oil begins flowing out of the upper drain hole.

Insert your upper screw plug, hand tighten, then tighten securely with your flathead screwdriver.

With the lower screw in your hand, remove the oil pump fitting. Quickly insert and tighten the lower screw.

Wipe everything down and properly dispose of your old oil lower unit oil.

**Caution**

There must be no water in your lower unit oil. If there is water in the lower unit oil and your boat is stored in the cold, the water in the oil will freeze and crack your lower unit, which is definitely a bad thing.

How do I troubleshoot my Mercury outboard engine?

If your Mercury outboard cranks, but won’t start, there may be an issue that needs correcting. 

Most likely, the cause is a low and dying battery. Remove the battery from its housing by first disconnecting the black (negative) cable, and then the red (positive). You can then check the voltage using a voltmeter– it should be at about 12.6 volts. Inspect the battery for damage and clean off any corrosion or other buildup with a wire bristle brush. 

Some types of residue can be removed with a mixture of water and baking soda at a ratio of 1 cup:1 tablespoon, respectively. Apply and scrub the mixture over the affected parts. If you choose to do this, be sure to very thoroughly dry the battery before reattaching the cables. Finally, if the voltmeter resulted in a low reading, charge the battery. 

In cases where your battery won’t hold a charge, it will of course need to be replaced. In the meantime, you may be able to start the engine manually.

Where can I learn more about Mercury Marine Outboard Rigging, Steering, Gauges, and Throttle Controls?

PartsVu understands that boaters want to learn how to perform their own Mercury outboard maintenance. From maintaining your Mercury outboard, Mercury sterndrive, and MerCruiser engines, there’s always something new to learn and save money. That’s why PartsVu offers our comprehensive blog, The PartsVu Xchange. 

Read up on the latest developments in boating, as well as search for everything you need to know about Mercury engine maintenance.

To get you off to a good start, these are some of the most important articles on how to adjust Mercury outboard throttle cable, an in-depth Mercury outboard rigging guide, and more:

• How to Check Hours on a Mercury Outboard - PartsVu
• The Ins and Outs of Rigging a Boat
• Mercury Marine Announces the Brand New ... - PartsVu
• Mercury Fuel System – 4-Stroke 100-Hour Service

What is Mercury Outboard rigging, and why is it important?

Mercury Outboard rigging refers to the various systems, components, and hardware used to connect and control the engine to the boat. This includes steering systems, throttle controls, gauges, wiring, and other accessories. Proper rigging is essential for ensuring safe and efficient operation of the outboard engine and the boat.

What types of steering systems are available for Mercury outboard engines?

Mercury outboard engines can be rigged with different steering systems, including mechanical steering, hydraulic steering, and power steering. Mechanical steering is the most basic and affordable option, while hydraulic and power steering provide smoother and more responsive control, particularly for larger boats and higher-powered engines.

Can I upgrade my Mercury outboard engine with new gauges and throttle controls?

Yes, Mercury offers a range of gauges and throttle controls designed to fit and integrate seamlessly with their outboard engines. Upgrading to newer, more advanced gauges and controls can provide better performance, reliability, and convenience.

How often should I check my Mercury outboard rigging components for wear and damage?

It is recommended to inspect the rigging components on your Mercury outboard engine regularly, at least once per season, for any signs of wear, damage, or corrosion. Replacing worn or damaged parts promptly can help prevent more severe issues and ensure safe and reliable operation.

What is a reed block, and how does it work in a Mercury outboard engine?

The reed block is a component in the intake system of a Mercury outboard engine that regulates the flow of air and fuel into the combustion chamber. It consists of thin reed valves that open and close rapidly in response to changes in pressure to control the airflow. A properly functioning reed block is critical for achieving optimal engine performance and fuel efficiency.

What are common problems with hydraulic steering for Mercury outboard engines?

While hydraulic steering systems for Mercury outboard engines are generally reliable, there are a few common problems that may arise. Here are some of the issues that Mercury outboard owners may encounter with their hydraulic steering systems:

1. Leaks: One of the most common problems is hydraulic fluid leaks. Leaks can occur at various points in the system, such as at the hoses, connections, or even the steering cylinder itself. Fluid leaks can result in a loss of hydraulic pressure, causing the steering to become stiff or unresponsive.
2. Air in the System: Air can enter the hydraulic steering system, leading to reduced steering performance. This can result in a "spongy" or "loose" feeling in the steering, where the wheel may have excessive play or lack responsiveness.
3. Steering Wheel Play: Excessive play in the steering wheel is another common issue. This can occur due to wear in the steering system components, such as the steering cylinder or linkage. Excessive play can make steering imprecise and affect the overall handling of the boat.
4. Steering Cylinder Issues: The steering cylinder, which is responsible for converting hydraulic pressure into mechanical force, can experience problems over time. These may include corrosion, internal seal failure, or binding of the cylinder components. Such issues can result in stiff or jerky steering.
5. Maintenance Neglect: Like any mechanical system, hydraulic steering systems require regular maintenance. Failure to perform routine maintenance, such as checking fluid levels, purging air from the system, or replacing worn components, can lead to problems and diminished performance.

What typically comes with a Mercury outboard rigging tube kit?

A Mercury outboard rigging tube kit typically includes various components and materials needed for installing and routing electrical cables and wiring harnesses in your boat. While the exact contents may vary depending on the specific kit and model, here are some common items you can expect to find in a Mercury outboard rigging tube kit:

1. Rigging Tube: This is a flexible plastic tube designed to protect and guide cables through the boat's hull.
2. Rigging Tube Connectors: These connectors are used to join multiple sections of the rigging tube together or to connect the tube to other components.
3. Grommets: Rubber grommets are included to provide a watertight seal where the rigging tube passes through bulkheads or other openings in the boat's structure.
4. Cable Clamps: These clamps are used to secure the cables within the rigging tube, preventing them from moving or chafing against the tube.
5. Tie Wraps: Also known as cable ties or zip ties, these are included to help secure the cables to the rigging tube and other areas of the boat.
6. Mounting Hardware: The kit may include screws, bolts, or other mounting hardware necessary for securing the rigging tube and associated components to the boat's structure.
7. Installation Instructions: A set of instructions or a user manual is typically provided to guide you through the installation process and ensure proper routing of the cables.

It's important to note that the specific contents of a rigging tube kit may vary, so it's advisable to check the product description or consult with a Mercury dealer to confirm the exact items included in the kit you are considering.

Are Mercury outboard shift and throttle cables the same thing?

No, Mercury outboard throttle and shift cables are not the same thing, although they are related and work in conjunction with each other. Here's a brief explanation of the difference between the two:

Shift Cables

Shift cables are responsible for transferring the shifting movement from the control lever or handle to the outboard engine's gearcase. They enable you to shift the engine into different gears, such as forward, neutral, and reverse. The shift cable connects to the shift linkage on the engine and allows you to control the gear selection.

Throttle Cables

Throttle cables, on the other hand, are responsible for controlling the engine's throttle or speed. They transmit the throttle input from the control lever or handle to the engine's throttle body or carburetor. By adjusting the throttle cable, you can increase or decrease the engine's RPM (revolutions per minute) and control the boat's speed.

While shift and throttle cables are separate components, they are often housed together in a single control unit, commonly referred to as a control box or control head. This allows for convenient and synchronized operation of both the shift and throttle functions from a single control lever or handle.

My Mercury outboard bogs down at full throttle - What causes Mercury outboard bogs at full throttle?

If your Mercury outboard engine bogs down or loses power at full throttle, there can be several potential causes. Here are some common factors to consider:

1. Fuel Delivery Issues: Insufficient fuel supply or a clogged fuel system can lead to bogging down. Check for clogged fuel filters, fuel lines, or a faulty fuel pump that may not be delivering an adequate amount of fuel to the engine.
2. Carburetor Problems: A dirty or malfunctioning carburetor can disrupt the fuel-air mixture, resulting in poor engine performance. Inspect the carburetor for clogs, debris, or worn-out components that may need cleaning or replacement.
3. Ignition System Malfunction: Issues with the ignition system, such as faulty spark plugs, ignition coils, or ignition timing, can cause the engine to bog down. Check and replace any worn-out or damaged ignition components as needed.
4. Air Intake Restrictions: A restricted or blocked air intake can limit the airflow to the engine, leading to performance issues. Inspect the air filter and ensure it is clean and properly installed.
5. Mechanical Problems: Mechanical issues like a worn-out propeller, damaged gearbox, or compression loss in the cylinders can also cause bogging down. Have a professional mechanic perform a thorough inspection to identify any underlying mechanical problems.

How to remove steering cable from Mercury outboard motors?

To remove the steering cable from a Mercury outboard motor, follow these general steps:

1. Disconnect the Battery: Before starting any work, disconnect the battery to ensure safety and prevent any accidental electrical mishaps.
2. Locate the Steering Cable: The steering cable is connected to the steering mechanism at the transom of the boat and runs to the steering wheel in the cockpit area. Identify the location of the cable and any access points or mounting brackets.
3. Loosen Cable Connections: Depending on the specific model and setup of your Mercury outboard, there may be various connections securing the steering cable. Loosen any clamps, bolts, or screws that hold the cable in place. This may include disconnecting the cable from the engine, steering mechanism, and/or helm.
4. Remove Cable End Fittings: Once the cable is loose, remove any end fittings that attach it to the engine or steering mechanism. This can involve unscrewing or unbolting the fittings and carefully sliding them off the cable.
5. Slide Out the Cable: With the connections and fittings removed, carefully slide the steering cable out of its mounting points and guide it through the boat until it is completely removed.

Note: The exact process may vary depending on the model and setup of your Mercury outboard. It's always recommended to consult the manufacturer's manual or seek professional guidance for your specific engine to ensure proper removal and installation of the steering cable.

Why is my Mercury outboard throttle stuck?

A stuck throttle on a Mercury outboard can be caused by several factors. One common reason is a buildup of dirt, debris, or corrosion around the throttle linkage or in the throttle body itself. Over time, these contaminants can restrict the movement of the throttle components, causing them to stick or bind. Regular maintenance and cleaning of the throttle system can help prevent this issue. Another possible cause is a malfunctioning throttle cable or control mechanism. If the cable is worn, frayed, or improperly adjusted, it may not move smoothly, leading to a stuck throttle. Additionally, the throttle control mechanism, such as the control box or handle, could be damaged or experiencing internal problems. In such cases, professional inspection and repair may be required to address the issue.

How does leaking Mercury outboard hydraulic steering fluid cause Mercury outboard hydraulic steering problems?

Leaking hydraulic steering fluid in a Mercury outboard can lead to various steering problems. The hydraulic steering system relies on the proper flow and pressure of fluid to operate smoothly and efficiently. When there is a leak, the fluid level can decrease, resulting in a loss of hydraulic pressure. This loss of pressure can cause issues such as increased steering effort, sluggish or unresponsive steering, or a loss of control over the steering mechanism.

In addition to pressure loss, leaking fluid can also introduce air into the hydraulic system. Air bubbles in the fluid can lead to foaming or aeration, which can further compromise the steering performance. Foaming can cause spongy or inconsistent steering feel and may result in difficulty turning the outboard in the desired direction.

Furthermore, leaking hydraulic fluid can damage internal seals and components of the steering system over time. This can result in more severe steering problems, including complete steering failure if left unaddressed.

What does Mercury outboard dual throttle control refer to?

The term "Mercury outboard dual throttle control" typically refers to a control system that allows the operation of two outboard engines with a single control unit. It is designed for boats equipped with multiple Mercury outboard engines, such as twin or triple setups.

The dual throttle control allows the boater to simultaneously control the throttle and shift functions of both outboard engines from a single control station. This centralized control simplifies the operation and maneuvering of the boat, providing convenience and ease of use. By utilizing a single control unit, the boater can adjust the speed and shift gears of both engines simultaneously, ensuring synchronized performance and responsiveness.

The dual throttle control system is designed to provide smooth and precise control over multiple Mercury outboard engines, optimizing their performance and enhancing the boating experience. It is typically equipped with features such as throttle synchronization, trim control, and integrated engine instrumentation to provide comprehensive control and monitoring capabilities for each outboard engine.