Changing a Fuel Filter at Sea

Our fuel system hates me. The previous owner didn’t change out his fuel often enough with the result that we have a science project growing in the bottom of our tank.

Yes children, algae CAN grow in diesel fuel. Algicides should have been added, but weren’t and now, our fuel filters clog with alarming frequency. This Fall, we plan to have the boatyard put a cleanout port in the side of the tank a clean the bugger down to bare metal. For now, we have the happy experience of having the engine shut down in the middle of Penobscot Bay from time to time.

When this happens, we have to open the portside locker and lean WAY down and open the fuel filter housing and extract the old filter. Then fresh fuel must be hand pumped into the housing and a new filter slipped in. After this, the housing must be topped up brimfull with fuel and the top screwed back on. This has to be done in a pitching boat. All excess fuel and the old filter must be put away to be later disposed of as hazardous waste.

If we do it right, there are no bubbles in the fuel system and the engine will restart and run. If not, we have to crank until we get the bubbles out and then start the engine. I’m told that truckers have this same problem and have found a better way to purge the filters, but I haven’t been able to find out what it is. Maybe this winter. Meantime, we’re going through a filter about every eight hours of running time and changing the filters every six. Lucky us.