Polishing Filter & Pump
I chose the Racor 900MA filter for my polishing filter housing. I also installed a drag needle vacuum gauge to monitor filter performance. The system is designed to run whenever the engine is running and turns the entire contents of the tank twice per hour. I also installed a switch so it can run independently of the engine or not run when the engine is on.
There are plenty of less expensive filters you could use that will work equally as well so don't feel you need to spend big bucks on a Racor. For me I prefer the Racor, as I know them in-side and out, and I know Hamilton marine has a massive stock of any part I would ever need for it.
Vacuum Guage With Drag Needle
The red needle is moved or dragged by the black vacuum needle. Once moved due to vacuum it simply stays where the highest vacuum was generated until you manually re-set it. Because this fuel pump is only running a polishing loop from the tank, through the filter then back into the tank, I can see very easily see when the filter begins to plug. A nice feature of a drag needle gauge is that I do not need the system running to view how plugged the filter is becoming.
After Three Years
The first season we ran the fuel polishing system for roughly 190 hours and the engine for 111 hours. The second season the polishing system ran for 300 hours and the engine for 122 hours (we have engine driven refrigeration so the engine runs more than most). This season we ran the polishing for 277 hours and the engine for 127 hours. These are the 2 mic polishing filter and secondary filter for the Westerbeke after 360 total hours of engine running time over a three year period. I inspected them each season then re-installed them just to see how long it would take for them to get "dirty". The primary Racor looks as new as the secondary Westerbeke filter.
The filter on top is the Westerbeke secondary on-engine filter. Both were installed at the same time. The on-engine filter is like new and at this rate could probably go five or more seasons before changing but I don't like to let the filter paper sit in fuel for that long so I'll change it bi-yearly after I am done my little "experiment" to see how long it takes them to get dirty.
I originally designed the polishing system for a 10 micron filter but the 900MA came with a 2 micron element. This element still looks almost brand new and had no additional vacuum after 767 hours of polishing. It has done an amazing job of keeping my primary Racor clean and my secondary on-engine filter clean as well. I see no reason to not continue using a 2 micron element in my polishing system.
It has become pretty clear to me that if you install a well designed polishing system, from the beginning, with a pick up tube at the dead bottom of the tank, that the tank can remain very, very clean for a long time to come.
In the previous years with this motor, before the polishing system, I had never once seen the Racor elements come out of my primary filter looking anywhere near as clean as they did at the end of the last three seasons. This is a real testament to the efficacy of a polishing system.
In summary I am running a 2 micron element in the Racor 900 polishing filter and a 10 micron element in my primary Racor 500 for the engine. All is purring along like a kitten and clean.