Are you cruising in areas with questionable fuel supplies? Are you storing your boat for long periods of time or have found condensation in your fuel tanks? If so, you definitely want to consider installing a fuel polisher.
Having a fuel separation and polishing system will save you time, money and OEM engine filters, not to mention stress over potential engine damage! We have a closed fuel polishing system for each supply, designed for simplicity and ease of maintenance, which is not connected to the engines.
CONTENTS:
What a fuel polisher does
How diesel fuel polishers work
Benefits of a fuel polisher
DIY system or buy a fuel polisher kit?
Components of a DIY fuel polisher
What a fuel polisher does
Keeping it short, a fuel polisher is a system that removes water, debris and bacteria from your diesel fuel. The fuel is then returned to the tank, ready for clean and efficient combustion.
How does a diesel fuel polisher work?
Fuel polishers pump diesel from the tank through a system where particles are filtered out based on the micron rating of the filters in the system. Then, based on how the fuel polisher is set up, the fuel goes through a process where centrifugal force and gravity are used to separate any water that's present from the fuel. After the fuel has passed through the system it's then returned to the tank, completing the process.
Some filters like the Racor 1000FH turbine series have a water separator built into the filter assembly, so a secondary water separation filter is not necessary. This type of "all in one" Racor filter housing is the variant you want to use in your DIY fuel polisher build to save money and time, and is the one supplied with some of the most expensive fuel polisher brands.
Benefits of using a fuel polisher on a boat
There are serious benefits to using a fuel polishing system on a marine diesel engine.
Keeps fuel clean for extended periods of time
Removes water to mitigate diesel bug
Extends the life of engine fuel filters
Keeps fuel injectors clean from particles and muck from diesel bug
Gives confidence that the engines will not cut out from bad fuel while under load or docking.
Able to clean fuel on board in remote areas
Keeps your fuel tanks cleaner for longer
Designing your own fuel polisher VS buying premade units
When installing a fuel polisher system you can either design and install your own or buy a premade kit and install that. Here's some of the benefits of having a DIY system.
The components can be spread around the engine bay or installation area, all in one manufactured polishers take up considerable space in a single chunk and are often joined together with fixed length piping, electronics and manifolds.
Components can be placed in areas for clear and comfortable service access.
You can choose to use the best components available without the overhead cost of a label and some pointless pretty custom anodizing.
The system can be simplified to reduce unnecessary parts that can fail.
Potential for large cost savings when compared to similar products from brands like Keenan Filters
Components of a fuel polisher
The key components of a fuel polishing system are the pump, diesel filter and water separator. You then need to connect all of that using adaptors, fittings and fuel hose. We'll go into each of these in more detail, but to start off here's what's in our system.
Our Yanmar 4JH45 fuel polisher
Since we have a catamaran we needed two of everything, one for each side.
Racor 1000FH Turbine Series Fuel Filter/Water Separator, purchased for $439.99 USD per unit.
Marco® UP6/OIL 12V Gear Oil Pump (SKU: MARM16408012) purchased for $351.20 USD per unit.
Fuel hose, adaptors, fixings and fittings to suit our layout
Fuse, relay and wiring to power the pump and run the ON/OFF switch back to the saloon
We also added a Racor pressure gauge which screwed directly into the Racor 1000FV10. Having this gauge allows us to monitor the system without having to pull anything apart and visually inspect it.
The Racor 1000FH was recently superseded by the 1000FV. Due to a fulfillment error we were actually sent one of each, and we prefer the 1000FH because it has a simpler design. The 1000FV has additional ports which are not necessary for this application.
Diesel filter housing
When choosing a diesel filter housing you want to consider these factors.
Flow rate is appropriate for the amount of fuel you want to clean
Size of the filter housing - Should have enough clearance around it to not impede maintenance or filter changes.
Size of the filters - Smaller filters have a smaller surface area so can block up faster if you do pick up bad fuel
Micron rating of the compatible filters
Which fuels it is compatible with
Can the filter housing be used under positive or negative pressure (will fuel be sucked through or pushed through)
Number of ports on the filter housing
Can it separate water or will you need a separate part for this
Global availability of replacement parts and filters
A clear viewing bowl is preferable
Water separator
Water can contaminate fuel in many ways including through condensation, leaks and issues during the refining process. As a result, removing water from fuel is a key function of a fuel polisher.
When choosing a water separator we're of the opinion that having it incorporated into the diesel filter housing like the Racor 1000FV10 has is the best option.
If you chose to have the water separator be an independent component, here's some things to consider.
Size of the filter
Size of the housing and how it would fit in your engine bay
Compatibility with fuels and hardware
Flow rate
Pressure rating
Having a water drain tap at the lowest point is preferable.
Pump
The fuel pump you choose needs to be able to move the fuel from the tank, through the polishing system and back to the tank so having a pump with the right amount of power is essential. Too little power can fail to move fuel through the filters while too much can cause filter housings or fittings to leak or fail, sometimes catastrophically.
Some things to consider when choosing which pump you want for your system.
Pump size
Lift height, i.e. how high can it pump fuel
Self priming is preferred
The orientation can it be mounted at
Is AC or DC power more suitable
Construction material - will it rust?
How heavy duty, reliable and serviceable is the pump
Compatibility with fuels
Adaptors, hose and fittings
The fittings, adaptors and hoses you need will vary depending on various factors including the size of your engine bay and the components in your system, in particular the thread pitch and size of the inlets and outlets. Our advice is to check the specifications of your components and what new items come with before buying anything.
When choosing fuel hose here's a few things to consider.
Internal diameter
Fuel rating
Pressure rating
Choosing a multi layered hose for abrasion resistance
Something that won't collapse under vacuum or swell under pressure
Once I had all my components I drew out a plan and listed what thread sizes the ports on my filters and pumps were, and what sized barbed hose fitting I wanted to maintain through out the system. Then I listing which adaptors and fittings I'd need to connect the system all together. Every boat will be different, but there are some common points you want to keep in mind.
You want to maintain a free flowing system with no bottlenecks.
Ensure the operational pressure stays within the tolerance of each par
Using a fuel rated thread sealant for all threaded joins
Do not use thread tape (PTFE tape, plumbers tape) anywhere in the system as it can damage pumps and contaminate fuel
How to install a DIY polisher
How you install your fuel polisher will vary depending on things like which marine diesel motor your yacht has, how the engine bay is laid out and what parts you chose for your system.
This video explains how ours is laid out and why I chose to set it up this way. We made it to provide feedback about our experience in case it was useful to others planning to make their own DIY fuel polisher.
Note, I've now added an additional part to the breather hose which is explained in the video description.
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