BoatHowTo · video

What this video covers

A marine diesel engine that can no longer reach wide-open throttle — despite clean primary and secondary filters — likely has fuel restrictions elsewhere in the system.0:18 Nigel Calder identifies three additional choke points beyond the filters: a screen on the pickup tube inside the fuel tank, a ball or check valve on the primary filter inlet, and a filter screen inside the lift pump.1:05 He notes that the symptom appearing specifically at wide-open throttle confirms a fuel-starvation cause, since that is when fuel demand peaks.1:46 Dirty filters also signal a contaminated tank, and Calder stresses that tank cleaning is the root fix — not just filter replacement.0:42 Jan Attenstedt and Calder recommend inspecting every connection and restriction point throughout the entire fuel circuit.1:35 Both point to the marine diesel engine maintenance course at boathowto.com, which they describe as having its largest module dedicated to fuel hygiene, tank sampling, and keeping tanks clean on older boats.2:09

More from BoatHowTo

How to keep you TANK CLEAN in the days of BIODIESEL.. | Ask The Expert with NIGEL CALDERAug 2026PARALLELING Conductors for AMPACITY - is that SAFE?? | Ask The Expert with NIGEL CALDERAug 2026ENGINE OIL turns BLACK right after Oil Change?? | Ask The Expert with NIGEL CALDERAug 2026Same LAYUP RECOMMENDATIONS for FAME and HVO bio diesel? | Ask The Expert with NIGEL CALDERAug 2026

From BoatHowTo — see the channel’s boat, crew, and every analysed video.

The Sailing Directory Newsletter

One email with the fleet's best finds — the moments, boats, and stories worth your watch time. Enter your own address to get your own copy.