The Owner of this 35 foot sailboat had been fighting diesel bug for four long years. Four years of blocked filters, fear of the engine conking out, and enough biocide to start a small chemical lab. So, we decided to go full exorcism: remove the fuel tank, clean it properly, and banish the bug once and for all.

The plastic tank was buried deep in an awkward locker, a classic “just reachable if you fold yourself in half” kind of job.

First, we needed to get the old fuel out. We rigged up a Clarke diesel transfer pump and rapidly sucked the contents out into jerry cans (disposing of it responsibly of course).

With the tank mostly empty and out (after some creative contortion and a fair bit of swearing), we gave it the full works. A steam cleaner blasted out the slimy sludge clinging to the bottom. Then, using a small Clarke drill-powered pump, we removed the mucky washdown water and leftover residue.

Next came upgrades: new engine hoses, a proper centrifuge filter, and best of all, a new inspection hatch. We used an adjustable drill mounted hole cutter to cut the 21cm hole in the top of the plastic tank. Once installed, that hatch will make future inspections and cleaning a breeze.

Tank refitted, (thanks to the bendy marine engineer chap, Ewan) hoses reconnected, system bled. The engine fired up, coughed to a stop, re-bled a bit more thoroughly and fired up again, because nobody is perfect.
Will this stop diesel bug forever? Who knows. But at least now, the owner can actually see the problem if it comes back, and maybe even clean it without removing half the boat.

Sometimes, the only way forward is to get your hands dirty. And trust me, ours were very dirty.

With thanks to Machine Mart for the tools to complete this job

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