I'm 67 and have been using diesel
engines since a preteen. Fuel polishing is just the popular new million dollar fix to a hundred dollar problem. Rarely is it necessary to open a fuel tank
and manually clean it. I've never seen it or even heard of it being absolutely necessary. Additionally the fuel is still safely burnable in your engine
Adding a good biocide will kill the growth and cause the water
to be absorbed by the fuel and the water will either show up in the Racor bowl or be consumed in the engine
without notice or harm.
The Racor filters should be available in 30, 10 and 2 microns. You can use your Racor and a small fuel pump
utilizing the supply and return lines going to your engine. If you don't have a vacuum gauge after the filters, add one in front of the pump. Run the pump with a 30 micron filter until you see a major rise in vacuum. If so change to another 30. If no rise go to a 10, etc. Then you have clean tanks.
My tanks are mild steel
, built in 1942 and hold 2000 gallons. The boat I have now sat for 6 years w/o care and little care before that. I added a double dose of algae-x in every tank with enough new fuel to stir things. I had to add a vacuum gauge and idled the mains and only got a small rise in vacuum with a new 30 filter.
I changed everything and did a sea trial, no issues. Now my tanks are so clean I run a 2 micron in my Racors. When I finally cut access holes, 2-3 years later, the tanks were clean. (I run 2 micron filters because of boiler/heating nozzles)
When I was a kid, my extended family
had a business breaking out mothballed ships and getting the steam machinery working. Sometimes delivering the ship to a yard or the new owners. When I knew enough, the emergency diesel
generators became my job. Some of the diesel was 20 years old. Other than filtering the fuel, we had no problems. But the fuel was better then.