Entry & progression
Course: RYA/MCA Approved Engine Course 2 — the second diesel course, taking the AEC 1 holder into more thorough servicing, the engine's electrical system, and systematic fault diagnosis. Entry: AEC 1 or equivalent basic diesel knowledge. Progresses to the Marine Engine Operator Licence (Small Vessel) and the small-vessel engineering CoC pathway.
The fuel path and its care
Fuel travels from the tank through a water-separating pre-filter, a lift pump, a fine secondary filter, the injection pump and finally the injectors that spray it into the cylinders. Each stage must be kept clean: the pre-filter drained of water, the primary and secondary filters changed on schedule, and the tank kept free of water and sediment. Because a diesel will not run on fuel with air in it, the engineer must be able to change filters and bleed the system confidently. Most fuel problems come down to water and dirt, so keeping them out is the priority.
- Understand the full fuel path: tank, water trap/pre-filter, lift pump, fine filter, injection pump, injectors.
- Change the primary and secondary fuel filters and bleed the system with confidence.
- Drain water and sediment from the tank and traps, and understand diesel bug and how to prevent it.
- Service the air filter, and understand the turbocharger's role and its need for clean air and oil.
TIP — Keep water out of the fuel Most fuel problems are water and dirt. Keep the tank topped up to reduce condensation, service the water trap, and treat the fuel if the vessel is laid up for a period.
WARNING — Diesel bug lives at the water line The microbial growth called diesel bug lives at the interface between fuel and any water in the tank, and it blocks filters. The way to prevent it is to keep water out of the tank.