Originally Posted by georgellop
It sounds like you are at the end of your rope (read "line").
You need to treat with biocide on a full tank of fuel (i.e. top it off) and install a polishing system. I am partial to filters installed in the vacuum side of the system and filters that match what you currently are using (i.e. RACOR). Once you complete the installation, rotate you fuel through the filter. Install vacuum gauges on your filters, this way you can monitor the rate at which you are clogging the filters and you'll know when the filter has served its useful life. You will soon see at drastic change in the rate at which the polishing filter is getting clogged. I would then polish the fuel on a regular basis.
I don't have this problem, but I have a plan to avoid it...
We are planning to circumnavigate in '09 and I have starting to buy stuff to improve the boat's systems. Currently, I have a Westerbeke W-52 with two steel keel tanks of 50 gallons each hooked to a manifold that allows delivery and return from either tank, or conversely, delivery from one and return to the other.
I also have a 40 gallon stainless steel one-time holding tank directly under the engine. I plan on removing the engine for a top overhaul, to paint the bilges, to install bigger batteries and to weld in cages for them (steel boat), and to put in a thrust bearing for an Aqua Drive coupler installation mated with a VariProp four-blade feathering prop: http://www.aquadrive.net/ad_features.html
Now here's the pertinent bit: I want to rehab the SS holding tank to a "day tank" for diesel that will at all times hold 40 gallons of pristine diesel. This means (beyond cutting inspection/cleaning ports and changing the hoses to fuel fills and vents) that I have an expanded manifold for the other two tanks to return fuel to the "pristine tank" via a polisher/filter.
I bought this yesterday at the Toronto Boat Show: http://www.ktisystems.com/filter_boss.html
It seems to meet my requirements for polishing, filtering under way, and a method whereby I can still keep the engine going while I keep motoring. There is also an alarm that goes off at a vacuum preset, i.e. if a rapidly clogging filter is about to cease passing fuel=time to switch the ballcocks to "reserve side".
The logic (and the justification for the $1,000 cost) is that a) diesel quality and cleanliness can only be expected to a certain degree in many places, and a Baja filter at the fill can do only so much; b) with the best will in the world, humid and/or stormy waters have the potential to let water into the fuel, and c) the WORST time to find out you have gritty/cruddy fuel is in rough, nasty seas on a lee shore with a shredded main. It's heinous outside, the shore/reef is near, and you have to power off. But the waves are swirling the tank contents into some sort of ur-soup. The engine misses...and stops.
Bang...your boat (and maybe the crew) are dead. For want of a filter, the ship was lost.
The AquaDrive and the beefy prop (that gives me a knot when sailing) and the uber-filter (which can be an auxiliary lift pump if needed or can quietly polish while on shore power) seem reasonable expenses when I consider the alternatives.