Polishihg the (Diesel) Fuel

[Boilermaker75]

Can someone explain what is involved in "polishing" the (diesel) fuel, when or how frequently it is recommended to do so, and what the approximate cost is?

If you buy a used boat and the (diesel) engine has 6,000 - 7,000 hours on it, how do you determine whether "polishing" the (diesel) fuel is warranted/needed?

Thanks for whatever insight, experience, and recommendations you have to share.

 

[Tom.B]

Polishing fuel is just the practice of repeated circulating the fuel out of the tank to an external filter using an external pump/filter rig. While it cleans the fuel, it does little to clean the walls of the tank. When you have bugs in your fuel, it is highly likely you have it in your tank. So polishing the fuel is only a short-term fix. Polishing, in my opinion, only needs to be done if you have a sudden problem from contaminated pump fuel or some kind of water intrusion. Well, also of you are getting your tanks cleaned which I do every two or three years. Should you discover your onboard filters clogging quickly, you COULD get a polish as a short-term fix. If it happens again, you need to get your tanks more thoroughly cleaned with high-pressure fuel streams and, if there is an access port, physically scraped and wiped.

Hope this helps.