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How to defeat Diesel Bug: One Tank, Two Pumps and a Lot of Elbow Grease | Practical Boat Owner
17 May 2025 · 16 min · 5K views
What this video covers
A boat that suffered repeated engine failures and multiple fuel-polishing treatments over four years finally has its diesel tank removed and cleaned to eliminate a persistent diesel bug infestation.0:15 The tank, a rotomoulded unit buried in a tight lazarette with no inspection hatch, is emptied using two pumps supplied by Machine Mart: a Clark heavy-duty fuel transfer pump and a lighter drill-mounted pump.1:17 All contaminated red diesel — visibly carrying water and sediment — is decanted into jerry cans and sent to an oil disposal facility rather than reused.3:05 Removing the tank requires undoing three brackets plus a hidden fourth, disconnecting Jubilee-clipped filler hoses, and rotating the tank past the rudder tube and cable runs; a fourth-year apprentice marine engineer, Ewan, squeezes into the lazarette to free the final fittings.4:54 Once out, a hole saw and Dremel cut an inspection hatch into the tank top, giving permanent access to the interior for future cleaning and inspection.11:22 The practical lesson: repeated fuel polishing fails when sediment accumulates in the far bottom corner near the pickup; full tank removal and an inspection hatch are the only reliable long-term fix, especially given the high bio-content of modern diesel.15:30
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