Cleaning a fuel tank

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Modifications & Maintenance & Repair fuel tank & Clean fuel tank

Chris posted this item on the Club Facebook page on 22nd December 2017.
See the photos at the bottom of this page.
Cleaned the diesel fuel tank today, oh does this feel good that she is clean on the insides. My Deltacraft has the original Volvo Penta 2002R motor. It took a few hours to clean the tank thoroughly, but well worth the effort.

Firstly I used a small hand pump to remove the bulk of the old fuel from the fill point beside the helm. I used a small liquid hand pump from Bunnings, catching all the old fuel and held in Jerry cans for appropriate disposal later.

Next I closed the tap at the bottom of the fuel tank in the engine bay, then undid the hose clamp holding the fuel delivery pipe that connects to the glass bowl filter on the front wall of the engine bay.

Once free I then opened the fuel tap to allowed the last of the fuel to drain into a 1L plastic container low in the bilge. The fuel coming out of the tank was very dirt indeed, it is a wonder the engine worked at all.

Next I removed and checked the cleanliness of both the glass bowl filter (which was putrid), as well as the main fuel filter on the motor, all good here. I ran some clean new fuel into the fuel tank to rinse out any remaining dirt and yuk, this ran out of the fuel line before the glass bowl filter. This tainted fuel also went into a 1L plastic container for removal from the boat.

I then reconnected the fuel line from the fuel tank to the glass bowl filter. Before replacing the main filter on the engine I filled it with new fuel and reattached it to the engine.

The system was ready for new fuel to be introduced to the now clean tank. As fuel made its way into the glass bowl filter I allowed the bowl to be a little loose to let air escape and the bowl be full of fuel. Once full, I wound up the screw under the bowl so it was tight not allowing any fuel to escape.

On the top of the assembly holding the main fuel filter there is a 10 mm bolt holding down the fuel delivery pipe from the fuel pump. This bolt needs to be loosened (anticlockwise) one or two turn then the plunger on the fuel pump activated until all air is vented from the system, the nut must be tighten (clockwise) again, but not too tight as it has quite a small shaft.

The job was messy and I needed lots of spare rags to keep the mess down.

If there is any point not clear I will be willing to give more detail. I was soooo surprised how dirty the fuel was in the tank, now I can go for a run on the lake after Christmas with confidence.

The primary filter was a saviour in this case. So much junk. It was a case of waiting for the motor to stop mid lake.

When refilling the fuel tank with new diesel I took the opportunity to mark 20 L and 40 L next to the fuel tank gauge in the engine bay, So now I have a good idea of how much fuel remains in the tank. Boosts my confidence on trips.

Cleaning the diesel fuel tank. The hand operated fuel pump for removing the majority of the fuel from the tank.

The tank showing fuel gauge sight tube and stop cock.

Primary fuel filter with glass cup. To drain the last of fuel from the tank remove the hose clamp from the fuel line running from the tank, ensure you have a container to hold the fuel, close the stop cock on the fuel tank if necessary. Once fuel is drained from the tank the glass cup can be removed by unscrewing the nut at the base of the glass and swinging the holding wire away. In this case due to age the nut was very tight and pliers were needed to start the nut turning. After cleaning the filter, when replacing the glass cup, ensure the cup if well seated on its rubber seal, otherwise fuel may escape.

Fuel filter on engine, note the 10 mm bolt on top where you can bleed air from the system if the nut is loosened and the fuel pump lever activated see next photo for fuel pump.

Fuel pump, showing manual activator on right.