Inboard Boat Engines: Starting Procedures And Common Issues

Starting an inboard boat engine is a complex process that requires careful precautionary measures to be taken. Inboard engines are more delicate than automobile engines and are more prone to safety issues due to their larger size. Before starting, it is crucial to perform inspections and preparations to prevent permanent damage from a cold start. This includes checking for gas leaks, ensuring proper ventilation, inspecting the battery, and replacing the fuel filter if necessary. Additionally, it is important to top off the fuel tank, drain and replace the oil, and inspect the gearbox fluid and steering components. Running an inboard boat engine out of water requires special tools and techniques to prevent irreversible damage to the engine.

How to Start an Inboard Boat Engine

Pre-launch checks: ensure the engine is prepared for the season ahead and test the engine before launch

Before launching your boat, it is important to carry out pre-start checks to avoid mechanical failure. Here is a list of checks to ensure your inboard boat engine is prepared for the season ahead:

Engine Checks

• Check all fluids, including engine oil, power-trim fluid, lubricant in the lower gear case, engine coolant, and power and hydraulic-steering fluid. Ensure that the fluids are at the correct level and are not contaminated.
• Check the colour of the engine oil. It should be clean and amber or gold in colour. If it is black, it needs to be changed. Milky or frothy oil indicates contamination by water and the engine should be serviced.
• Check the propeller shaft for straightness by standing directly behind it and rotating the propeller. If it is bent, take it to a prop shop. Also, check for fishing line or debris around the shaft.
• Check belts and hoses for cuts, splits, or fraying.
• Check water hoses for age, brittleness, and dry rot. They should be pliant yet firm, not mushy.
• Check the engine coolant and top it up if necessary.
• Check for any leaks in the engine compartment, including oil or coolant leaks.
• Check the battery for a full charge. If it has been unattended for a while, it may have discharged. Clean the battery posts and cable connections with a battery terminal brush.
• Check the fuel filter and replace it if the boat has been stored or winterized.
• Top off the fuel tank and add a fuel additive to absorb any contaminants or water.
• Drain the oil and replace the oil filter if the boat has been sitting for a long time or has been winterized.
• Check the out-drive gearbox fluid level and inspect all grease fittings on the steering arm, motor pivot points, and throttle linkage. Ensure that the connections are lubricated, secured, and move freely.
• If your engine has a transparent water separator/filter in the fuel line, check the transparent bowl for water or dirt and drain off any contamination.
• Check the gearbox oil level with a dipstick. Refer to the engine manual for the correct type and grade of oil to use.
• Check the engine oil level with the dipstick and top it up if necessary.
• Check the spark plugs and replace them if necessary.
• Check the raw water filter for clogs, as this can restrict the flow of cooling water and cause the engine to overheat.

Boat Checks

• Check the weather forecast for the area and timeframe during which you will be boating.
• Check the hull for cracks or other damage.
• Ensure the steering and throttle controls are operating properly.
• Check the electrical system and lights to ensure they are working properly.
• Check for any fuel leaks from the tank, fuel lines, and carburetor.
• Check the propulsion and cooling systems.
• Check hose connections for leaks or cracks, and ensure hose clamps are tight.
• Drain all water from the engine compartment and secure the drainage plug.
• Ensure you have enough fuel for your trip, including a reserve.
• Check that you have a fully charged engine battery and fire extinguishers on board.
• Make sure you have the required number of life jackets or PFDs (Personal Flotation Devices) for all persons on board and that they are easily accessible.
• Check that all required safety equipment is on board, in good working order, and easily reachable.
• Ensure you have a first-aid kit, basic tools, and spare parts, including plugs for all through-hull fittings.
• Check that you have official nautical charts and related publications.
• If equipped, ensure the engine shut-off line is in good order.
• Ensure the weight of persons and gear is evenly distributed and balanced, with most of the weight kept low.
• Check that all boat operators have the required documentation, such as a Pleasure Craft Operator Card or other proof of competency.
• Leave a float plan with a reliable contact, including details of your intended route and timeframe.

Use a circular plunger or motor flusher to create a strong suction of water for the engine

A circular plunger or motor flusher is an essential tool for starting an inboard boat engine on land. It creates a strong suction of water, preventing the motor from running dry. This process is known as "fake-a-lake", as it mimics the conditions of a lake, allowing the inboard engine to start safely. Here's a detailed guide on how to use a circular plunger or motor flusher to create a strong suction of water for your inboard boat engine:

Choosing the Right Tool

Firstly, you can choose between a circular plunger and a motor flusher. The circular plunger resembles a standard toilet plunger, with an outlet that connects to a garden hose. On the other hand, the motor flusher, also known as an inboard motor flusher, looks like a pair of earmuffs. It connects to the motor's inlet vents and the boat's water intake, creating a strong suction.

Preparation

Before you begin, ensure you have the right equipment. You will need a garden hose and either the circular plunger or the motor flusher. Inspect your garden hose for any leaks to ensure it works properly. Additionally, park your boat in a flat, open area, and mount it on a trailer to access the water intake.

Connecting the Equipment

If you're using a circular plunger, connect the hose to the open part of the plunger and tighten it securely. For a motor flusher, attach one end to the water intake and the other to the engine's inlet vents. In both cases, ensure that the connection is tight and secure to prevent accidental sliding or leakage.

Water Supply

Turn on the faucet or water supply to test the flow. Then, go under the boat and locate the water intake, which is the hole where the engine sucks water. This is usually near the boat motor.

Positioning the Plunger or Flusher

Position the plunger or flusher securely over the water intake. Adjust the leg height accordingly, ensuring that the water intake hole is completely covered. Make sure the tool is stable and won't slide or move when the water pressure increases.

Starting the Engine

Once the plunger or flusher is in position, turn on the water supply to its maximum level. You should see water overflowing in the plunger's cup or the flusher. Now, you can start the inboard engine. As the motor runs, the pressure of the outgoing water will slightly decrease, indicating that the engine is working correctly.

Final Steps

After running the engine for a few minutes, turn it off, along with the water supply. Remove the plunger or flusher from the water intake and allow it to air dry completely before storing it for future use. Remember to always test your inboard boat engine before launching it into the water to ensure its proper functioning and prevent irreversible damage.

Check for leaks and tighten any fittings

Before starting an inboard boat engine, it is important to check for leaks and tighten any fittings. This is a crucial step to ensure the engine runs smoothly and prevent any irreversible damage.

Firstly, locate the water intake hole, which is usually near the boat motor. Cover the intake hole with the muff plunger, ensuring it is tightly secured in place. Adjust the leg height as needed, making sure the leg is firmly against the ground. Check that the water hole is completely covered, and the muff is tightly secured so that it doesn't slide when the water pressure increases.

Next, turn on the water supply and observe if water is pouring down from the muffler. If it is, you can proceed to the next step. If not, check for leaks in the hose and ensure all connections are tight and secure.

Once the water supply is confirmed, you can start the engine. Keep an eye on the muff plunger to ensure it remains in place and doesn't fall off. Also, monitor the temperature gauge; if the temperature rises above 200 Fahrenheit, shut off the engine immediately to prevent overheating.

After running the engine for a few minutes, turn it off, then switch off the water supply. Finally, remove the flusher and disconnect the garden hose. Allow the engine to air dry completely before storing it away.

Check the battery for a full charge and clean the battery posts

To check the battery for a full charge, use a voltmeter or multimeter. A healthy marine battery should register between 12.6 and 12.7 volts. It is important to test the batteries after they have been sitting for at least an hour to get an accurate reading of the resting voltage.

To clean the battery posts, start by disconnecting the terminals. You can then use a wire brush, battery terminal brush, or stainless steel wool to clean the battery posts and terminals. After cleaning, apply a thin layer of petroleum jelly or grease to the terminals. Finally, reconnect the cables to the appropriate posts, ensuring that the terminals are clean and tight.

It is recommended to check for corrosion and clean the battery posts and terminals every four to six months. This is an important step in maintaining your boat's battery and ensuring it functions properly.

Additionally, it is worth noting that some boats may have a built-in battery monitor that can provide information on the battery charge level.

Check the fuel filter and replace if necessary

Checking the fuel filter is an important step in preparing your inboard boat engine for the season, especially if it has been sitting idle for a while. Here's a detailed guide on checking and replacing the fuel filter:

Step 1: Understand the Importance of Fuel Filter Maintenance

The fuel filter plays a critical role in ensuring your boat engine receives clean fuel, free of contaminants and water. Modern engines, both gasoline and diesel, rely on clean fuel to prevent clogging of the injectors, which can lead to performance issues and damage.

Step 2: Inspect the Fuel Filter

Before starting, carefully inspect the fuel filter for any signs of damage, wear, or corrosion. Look for any cracks, leaks, or debris accumulation. If your boat has been in storage or winterized, it is recommended to replace the fuel filter. Condensation can build up quickly in boat fuel lines and filters, leading to trapped water, which will cause starting issues.

Step 3: Replace the Fuel Filter if Necessary

If the fuel filter shows signs of deterioration or if it has been a while since the last replacement, it is best to replace it. Refer to your boat's manual for specific instructions and the recommended replacement schedule. Fuel filters are typically replaced with a similar OEM-equivalent filter, ensuring compatibility with your engine.

Step 4: Consider Upgrades

When replacing the fuel filter, consider installing an inline fuel filter with a higher micron rating, such as a 10-micron fuel filter/water separator. This can help capture smaller contaminants and provide additional protection for your engine.

Step 5: Clean and Inspect Related Components

While working on the fuel filter, take the opportunity to clean and inspect related components, such as fuel lines and hoses. Look for any signs of cracking, abrasion, or vibration-related wear. Ensure that all connections are secure and free of leaks.

Step 6: Refill and Test

After replacing the fuel filter, refill the fuel tank and add a fuel additive to absorb any remaining contaminants or water. Test the engine by attempting to start it and letting it run slightly above idle for several minutes. If the engine runs smoothly without issues, you can proceed with launching your boat.

Remember to consult your boat's manual for specific instructions related to your particular make and model. Safe boating!

Frequently asked questions