Plastic Classic Forum

I am thinking about a fuel polishing system for my Alberg 37. I have a petcock at the bottom of the tank that I could convert to a fitting for intake into the polishing system. I was thinking of a facet electric pump, then a filter, then back into the tank, perhaps by teeing into the existing diesel fuel return line. My questions are:

1) Should the pump go before or after the filter?
2) What is the best kind of filter to use?
3) Are there any pitfalls teeing into the fuel return line?

Thanks.

George

1 Filter before the pump so if you have dirty fuel you do not run the risk of plugging the pump especially if you plan to use a small facet pump.

2 I would go with the Racor 500 series filter.Although not the smallest Racor it has a good water separator, is easily drain-able and super easy to change a filter element. Racor makes smaller filters but cartridge replacements are expensive and not quite as easily done. i would even recommend if your budget allows to change both your Eng primary and polishing filter to the same 500 series so you can carry the same spares.

3 Be sure that the return line into the tank is appropriately sized to handle the return flow from the Eng as well as the new polishing system . many boats are set up with common supply and return lines run to a manifold to supply Eng/Gen so a polishing system should be fine. it is a good idea to make sure the return line goes all the way to the bottom of the tank.

jetboy52 wrote:
1) Should the pump go before or after the filter?

This all depends upon which polishing filter you chose and there are many. I chose a Racor 900MA and Racor wants to see the pump on the vacuum side for the best performance of water extraction.

jetboy52 wrote: 2) What is the best kind of filter to use?

They will all work to clean crud from the fuel so it then comes down to the maintenance, water extraction and filter costs. For me it was an easy decision. The Racor turbine filters are proven, easy to work on, easy to get parts for, you can see your fuel, and easy to change the element on. Some of the cartridge filters like the ones made by Cummins/Fleetguard are also good but expensive and lack some of the features that the Racor has. Plus, for me, Hamilton stocks a huge supply of all things Racor.

jetboy52 wrote: 3) Are there any pitfalls teeing into the fuel return line?

Yes, there can be. Depending upon which pump you choose and whether you decide to go high flow/turnover or low flow/potentially better water extraction will depend a lot on how well teeing into the return works. I prefer a true high flow system to keep the fuel & tank really clean and I filter it down to 2 micron.

With a high flow system, my Carter pump is 72 GPH, and with this I can turn my tank twice per hour. This flow rate is enough to foam the fuel, if it is not returned into the fuel, meaning using a dip tube to return it below the fuel level in the tank. When I designed my new tank I added supply & return tappings specifically for a fuel polishing system. The return is via dip tube to prevent or greatly minimize foaming of the fuel and the supply picks up within 1/8" of the dead bottom of the tank not 1" + off the tank floor as the engine pick up does. This allows real cleaning of the entire tank contents and does not cause any foaming.

There are some pics of how I did this on my site: http://www.pbase.com/mainecruising/repl ... _fuel_tank

I use a Fleetguard or Danaldson water separating filter as a primary filter for my Racor500. I find the truck filters to be cheaper than the Racor but you don't have a clear bowl to see "stuff". I got the filter head at a truck parts place for under $5o. You could use a similar setup to polish fuel as well I suppose. The price of a Racor 900 in Canada made my eyes water so I had to adapt however, I find you can't go wrong following Mainesails advice.

I have just such a system on Deep Blue. I use a racor 125 primary followed by a facet fuel pump, and finished with a 2 micron Perkins engine filter. Each spring I filter the fuel for about 3 hrs and then replace the filter elements. When I built the system I put a tee into the fuel return line and the fuel output line. This proved to be too many valves and too many connections; (KISS). A short piece of hose looped from the fuel output to the tank return now does the trick. This system has worked well for 5 years now. Hope this helps Phil