Boat Engine Checks: Dry Dock Maintenance Guide

Testing a boat engine on land is a straightforward process, but it requires careful preparation and a basic understanding of the engine's components. This article will outline the steps to test a boat engine on land, including essential maintenance checks to ensure the engine's longevity. Whether you're a new boat owner or considering purchasing a used boat, understanding how to check a boat engine on land is crucial.

Check for engine hours

Checking your boat's engine hours is crucial to ensure the longevity of your boat. The engine hours refer to the number of hours your boat has operated over its lifetime. While modern engines will track this information for you, it is important to know how to access this data to ensure you are performing essential maintenance and not risking damage to your boat.

Step 1: Determine If Your Boat Tracks Engine Hours

Most modern boats come with an hour meter that records the number of hours the engine is running. This data is stored in an "engine run-time log" in the engine computer. However, some smaller outboard engines may not have this feature, so it is important to check.

Step 2: Locate Your Engine Hour Tracker

There are a few places where you could find your boat's engine hours, depending on the type of boat you own.

• Dash: The total engine hours are often displayed on a digital instrument on the dash. This data may also be displayed on a third-party or multi-function screen.
• Instrument Panel: You may need to consult the user's manual to find the hour meter, which will display the engine hours.
• Speedometer: Some boats may have a speedometer or tachometer with an LCD screen that displays engine data, including hours. However, be aware that some displays only record when the ignition key is turned on, not the actual time the engine is running.
• Analog Hour Meter: For older boats, an analog hour meter may be located on the engine itself or in the engine compartment.

Step 3: Consult a Boat Dealer

If you are having trouble locating the engine hours or want more detailed information, you can visit a boat dealer. They can use proprietary software to access the engine's data using a laptop or scan tool. This is especially useful when buying a pre-owned boat, as you can see how the engine has been run and if it has been abused.

Step 4: Check Your Boat Manual

Finally, be sure to check your marine engine owner's manual to understand the recommended maintenance schedule based on engine hours. This will help you keep your boat in excellent condition and extend its lifespan.

Test an outboard motor without a boat

Testing an outboard motor without a boat is possible, but it requires careful setup and should only be done by those with experience.

First, the motor should be securely mounted to a sturdy platform. A large bucket of water should be placed underneath, ensuring the propeller is fully submerged. The bucket should be big enough to submerge the impeller/water pump housing, not just the propeller.

If the motor has not been started in a while, you may need to use starting fluid. Remove the rubber shields over the spark plugs and unscrew them. Spray starting fluid into the spark plug cavity and the air filter. If the motor still won't start, you may need to jump-start it using a 12V battery, connecting jumper cables to the metal screw heads near the starter.

It is important to note that running an outboard motor without a water source for an extended period can cause damage due to overheating. Therefore, it is recommended to attach a hose to the motor's water intakes to flush in water. Newer motors may have built-in hose attachments. If not, you can use motor flusher muffs, which look like earmuffs connected by a long, V-shaped rod. Ensure the muffs are wet to achieve a better seal.

Before starting the engine, turn on the water and put the engine in neutral. Check that there is a stream of water flowing out of the top of the motor, indicating that the water pump is functioning correctly. If there is no stream, turn off the engine and fix the water pump.

When you are ready, start the engine and run it for 5-10 minutes, or according to the manufacturer's recommendations. Keep the engine in neutral and be cautious around the propeller. Do not leave the engine running unattended, and always turn off the engine before turning off the water supply.

Additionally, it is recommended to flush the motor after each outing to prevent the buildup of salt, silt, and other debris.

Check for engine issues

Checking for engine issues is a crucial step in boat maintenance. Here are some detailed instructions to help you identify and address common engine problems:

Engine Won't Start

This is often an electrical issue. Check the kill switch and ensure the shifter is in neutral. Inspect the starter switch; sometimes, a dash-mounted ignition switch may be loose, causing the entire mechanism to turn with the key. Tighten any loose nuts or screws. If the starter groans but doesn't engage, the issue could be a low battery or a loose/poor connection.

Boat Engine Is Sputtering and Losing Power

This is likely due to a filter problem or fouled plugs. Replace the in-line fuel filter with a spare. If you don't have a spare, remove and clean the filter element of any debris and drain accumulated water. For inboard/outboard (I/O) engines, remember to vent the engine box thoroughly before restarting to avoid a clogged filter.

Boat Engine Is Overheating

This is usually caused by a lack of water flow in the cooling loop. Outboards, small inboards, and I/Os don't have radiators; they use the water they float on for cooling. Locate and clear any obstructions in the raw water intake, such as weeds, mud, or plastic bags. Also, check for loose hose clamps or damaged hoses, which can slow water flow and cause moisture spray around the engine.

Boat Motor Stopped Suddenly

Start with simple checks: ensure the lanyard key is not loose on the kill switch, and check the ignition switch and its fuse or breaker. Corrosion is a common issue, especially at the 'business end' where the large wires live. Clean the connections with a wire brush.

Vibration from the Engine Prop

This is often caused by damage to the prop, such as a nick or gouge, causing imbalance and vibration. Remove any fishing line or towrope that may have snarled the shaft. If the prop appears good, there may be unseen distortion or damage causing cavitation and vibration. Slow down and focus on getting to shore.

Engine Won't Shift into Gear

If you have electronic controls, the issue could be a blown fuse. For mechanical cable shifts, check the linkage. Start at the gearbox and ensure the cable is attached to the shift lever on the transmission housing. Try wiggling a stuck cable free, or shift manually at the engine/transmission.

Trim Is Stuck on the Engine

If it's not a bad fuse, it's likely a mechanical/hydraulic issue. Locate and open the trim release valve near the base of the outdrive/outboard to release pressure from the hydraulic loop, allowing the drive to tilt.

Lack of Preventative Maintenance

Create a checklist with your dealer to keep track of maintenance tasks and reduce the chances of being stranded. Regular maintenance is key to a better-running engine and longer engine life.

Monitor engine temperature

Monitoring the temperature of your boat engine is crucial to ensure longevity and performance, especially in challenging environments. In this guide, I will take you through the process of monitoring your engine temperature using tools such as an infrared thermometer and the versatile ESP32 microprocessor.

Using an Infrared Thermometer

An infrared thermometer is an important tool for any boat owner. It can be used for various troubleshooting tasks on a boat, such as refrigeration, stuffing box, and electrical troubleshooting. Additionally, it can be used to measure the engine temperature. Here's how you can use it to create an engine temperature baseline:

• Measure various marked locations on the engine when it is running well and record these temperatures in a notebook, tablet, or computer.
• Measure the raw water intake temperature, which is the temperature of the elbow leading to the sea strainer. This will give you an idea of the water temperature your raw water pump sees.
• Mark each measurement spot with a dot made by a Sharpie marker to ensure repeatability in your measurements.
• Maintain a consistent aiming distance when taking measurements for more accurate readings.
• Measure the heat exchanger raw water outlet temperature, which is the temperature of the raw water circuit as it exits the heat exchanger.
• Measure the temperature of the wet side of the exhaust elbow, which is where the raw water circuit injects cooling water into the hot exhaust gases to prevent melting the rubber hoses inside your boat.
• Measure the temperature of the dry side of the exhaust manifold, which is the actual temperature of the dry exhaust gases before they are mixed with raw cooling water.
• Compare the temperature differential between the wet and dry sides of the exhaust elbow. If this differential increases over time, it may indicate a clogging issue.
• Measure the temperature of the thermostat housing, both the upper and lower sides, to understand how the thermostat is operating and at what temperatures it is opening and closing.
• Measure the temperature of the temperature sending unit, which is the brass sensor that sends the temperature data to the temperature gauge on your engine panel.
• Measure the temperature of the raw water pump, which should normally be a little higher than the ocean temperature but still within a 10-degree spread.
• Measure the temperature of the hot water heater supply and return lines. The differential between these two temperatures should be within 5 degrees before creating your baseline assessment.

Using the ESP32 Microprocessor and DS18b20 Sensors

The ESP32 microprocessor can be used as a remote hub for engine temperature monitoring, and it offers the advantage of connecting a wide variety of sensors. In this setup, you can use the DS18b20 one-wire sensors, which can handle temperatures up to 125°C and are relatively waterproof. Here's how you can set it up:

• Install temperature sensors around your engine to monitor coolant temperature, temperature near the thermostat, raw water elbow temperature, and alternator temperature.
• Set alerts for abnormal temperature rises, such as at the raw water elbow, to indicate issues like a worn impeller, intake blockage, or no water flow.
• Review historical data on engine temperature and oil pressure trends to track and analyze performance and engine health.

By following these steps and using the right tools, you can effectively monitor the temperature of your boat engine, ensuring early detection of potential issues and maintaining optimal performance.

Check for engine maintenance

Regular engine maintenance is essential to ensure the longevity of your boat. Here are some detailed instructions to check for engine maintenance on land:

Check Engine Hours

Before performing any maintenance, it's important to know how many hours your boat engine has been in operation. This is crucial as it affects the longevity of your boat and helps you stay on top of essential maintenance. Modern boats have an hour meter that records the number of hours the engine is running. This data is recorded in an "engine run-time log", which includes engine warning alarms, fault codes, and instances of overheating. You can locate this information on the dash, instrument panel, or speedometer of your boat.

Check Oil and Fluid Levels

It is recommended to check the oil and fluid levels before every outing. Clean oil extends the life of your engine, so it is important to change it according to the owner's manual. As the engine ages, increase the frequency of oil changes. Other fluid levels to monitor include power steering fluid and coolant.

Battery Maintenance

The battery is the heart of your boat, so it is crucial to keep it well-maintained. Check the battery at least once a year, especially during the boating season. Recharge the battery if it is weak when starting the engine. Clean the battery terminals by disconnecting them and removing corrosion with a wire brush. Tighten any loose connections.

Inspect Engine for Wear and Tear

Regularly inspect the engine for signs of wear and tear. This includes checking hoses, belts, and bolts for any damage or looseness. Ensure that everything is fitted properly, including the engine cover. Look for any corrosion and address it promptly.

Use Marine Parts Only

When replacing electrical parts, use only marine parts and not automotive electrical parts. Using automotive parts may cause a spark that could ignite a fire. Marine parts are designed to be used in boats and can withstand the unique conditions of a marine environment.

Keep the Engine Clean and Tuned

In addition to the maintenance checks above, it is important to keep your engine clean and properly tuned. Refer to your owner's manual for specific recommendations and a maintenance schedule.

By following these steps and staying on top of engine maintenance, you can help ensure the longevity and optimal performance of your boat.

Frequently asked questions