Half way thru a 10 day cruise and had a Racor filter clog with brown slime. Changed filter and have motored for 5 hrs with no problems. Is it possible to "self polish" with my Racor by leaving it running while on the dock tonight ?
Lots of helpful replies, and I thought of a "baseline" pair of concerns.
At the slip the 'gunk' in the tank bottom that you want to filter out will just stay in place and unless you have a way to sweep an intake all around the tank bottom you will not get at it. So the lack of agitation will be a problem.
Then there is the quantity of fuel you would potentially filter with the system when the engine is running. Our mechanic once told me that our small diesels only return a small quantity to the tank via the return hose. These engines do not burn very much fuel, and little of what goes to the lift pump returns to the tank anyway.
The fuel that *does* get pumped to the engine is already filtered twice before it reaches the return line. I had the factory Universal M25XP, for decades,
IF... you have spare filters with you, and due to motoring in steep seas the tank is well-agitated, you will catch most sludge in your filters. But then, you might find yourself changing filters in a rolling boat ( Gag !) .
Best, IMHO, to have a clean-out port on the tank top, where you can just reach in with a flexible pickup and pump out the bottom layer yourself every year or two. Or three. And, if you have a 6" clean out port, a professional can make a much quicker and better job of cleaning with his pump/filter/external tank system, also.