Cleaning the fuel tank after 36 years Back to Projects Back to Valhalla's Mooring Page
Having experienced a clogged fuel system which forced us to sail back through the night for 100KM to a known anchorage, it was now time to do a complete cleaning of the fuel tank ... the first time in 36 years
The fuel tank is built into the keel and has one baffle at the aft end just forward of an inspection port which gives minimal access to the tank for cleaning.
I made the decision to cut into the top of the tank to gain better access for cleaning.
First step was to remove the old diesel.
I used an electric fuel transfer pump assembly I had previously made.
The transfer pump is an automotive diesel fuel pump with switch and powered via a cigarette lighter connection. Here I am using the boat tank pickup tube to transfer the diesel through a Baja Filter into containers. 20 liters takes 12 minutes.
As an aside, I use this transfer pump for easy filling of the fuel tank from containers. The hose goes into a PVC pipe, closed at the bottom and with a multitude of 1 mm holes at the bottom of the pipe to filter out any junk in the container.
After removing the hoses for the injector overflow, fuel tank pickup and air vent, I used the largest hole saw I had (55mm) to cut out four holes on the corners of the intended opening.
Using a hand saw I cut out the opening.
Looking forward in the tank the sludge can be seen covering the pickup tube, walls and bottom of the tank.
Needing some light in the tank while working through the small openings, I removed the mechanical fuel gage, fabricated a small 5W light bulb extension and inserted it in the fuel gage hole.
Reaching through the cutout I had made was a bit difficult to reach the forward end of the tank. An extension to the scraper was needed.
The round inspection port gives access to the aft end of the tank with a baffle just forward of it.
With a bit of effort the tank interior was scraped to dislodge the sludge. Here Rose's small hands and arms come in handy!
After scraping the tank was scrubbed with Scotchbrite pads, wiped down with kerosene, sopped out with rags and, after some time to dry, cleaned with a vacuum cleaner. The result was satisfying.
Next was to cover the hole that had been cut. The available scrap fiberglass was a bit thick but a taper was ground on one end to provide clearance for the hoses that would pass over it.
A layer of marine epoxy was applied to the edges of the hole and the edges of the cover before 'clamping' in place.
With the fuel gage cover replaced (sans the fuel gage which I never use) and the hoses reconnected the job was done.
The fuel I had removed was given two more pours through a Baja filter before returning to the tank. I took the time to add the fuel in 10 and 20 liter increments so a dip stick could be calibrated.
End of another SLOJ (shitty little odd job). !!