Maintaining your boat’s engine is crucial for its longevity and performance. One of the essential tasks is changing the filters and priming the system, which ensures that your engine runs smoothly and efficiently. In this guide, we’ll walk you through the process of changing the filters on a Yanmar 4JH4E engine and priming the system, as demonstrated by Amanda from Amanda’s Sailing Adventure.

1. Preparing for the Task:

Before you begin, it’s essential to gather all the necessary tools and ensure that you’ve shut off specific systems to prevent any mishaps.

• Shut Off the Raw Water Engine Intake: Before starting any maintenance, ensure that the raw water engine intake is closed. This step is crucial when working on the impeller.
• Turn Off the Fuel: Locate the fuel shut-off, which, in Amanda’s Hunter 44 boat, is found underneath the bed. Ensure that both the engine and the gen set fuel systems are turned off.

2. Changing the Impeller:

The impeller is a vital component, and changing it regularly can prevent potential engine issues.

• Remove the Cover Plate: Start by removing the impeller’s cover plate. This will give you access to the impeller and the o-ring.
• Extract the O-ring and Impeller: Using a suitable tool, gently pull out the o-ring followed by the impeller. Some people use a tool known as the “Jesus tool,” but other methods can work just as effectively.
• Clean and Prepare: Once the old impeller is out, clean all the surfaces with a wire brush to ensure a smooth fit for the new impeller.
• Insert the New Impeller: Before inserting the new impeller, apply some glycerin to it. This lubrication helps the impeller slide in more easily. Once lubricated, push the impeller into its slot.
• Replace the O-ring: After the impeller is in place, insert a new o-ring.
• Reattach the Cover Plate: Finally, return the cover plate to its original position and ensure it’s tightened securely.

3. Changing the Fuel Filter:

A clean fuel filter ensures that your engine gets clean fuel, free from any contaminants.

• Remove the Old Filter: Using a suitable tool, unscrew and remove the old fuel filter. Ensure that the gasket or ring from the old filter isn’t stuck in the housing.
• Insert the New Filter: Take a new filter and fill it up with fresh diesel. Once filled, screw it into place.

4. Changing the Raycor Filters:

Raycor filters are essential for filtering out any contaminants from the fuel.

• Unscrew the Old Filters: Start by unscrewing the old Raycor filters. Be prepared for some diesel spillage, so have a cloth or container ready.
• Check the Gasket: Ensure that the gasket from the old filter is not left behind. Remember the orientation of the gasket as you’ll need to place the new one in the same way.
• Replace with New Filters: Screw in the new Raycor filters securely.

5. Priming the System:

After changing the filters, it’s essential to prime the system to remove any air that might have entered during the process.

• Open the Bleed Screw: Locate the bleed screw on the fuel filter housing and open it slightly.
• Pump the Primer: Manually pump the primer (usually a hand lever or button on the fuel pump) until you see a steady stream of fuel without any air bubbles coming out of the bleed screw.
• Tighten the Bleed Screw: Once you see a steady flow of fuel, tighten the bleed screw.
• Start the Engine: Turn on the engine and let it run for a few minutes. Monitor for any irregularities in performance or unusual sounds. If the engine runs smoothly, the priming process is complete.

Conclusion:

Regular maintenance, including changing filters and priming the system, is essential for the optimal performance of your boat’s engine. By following these steps, you can ensure that your Yanmar 4JH4E engine runs smoothly and efficiently for a long time. Always remember to take safety precautions and refer to the engine’s manual for any specific instructions.