Fuel supply system stores fuel and delivers it to the engine cleanly and consistently. Whether diesel tank with supply and return lines, natural gas feed with regulators, or hybrid system, the goal is the same. A sealed properly routed delivery path that maintains stable flow and pressure when the generator takes load.

• Fuel Storage: Tank must store adequate fuel volume for required run time while preventing contamination from water, sediment, or microbial growth that degrades fuel quality.

• Contamination Prevention: Proper tank design with sealed fill caps, water drains, and ventilation prevents contamination while allowing thermal expansion without creating vacuum or pressure.

Contamination is a major factor including water or sediment in liquid fuel storage or debris in piping and regulators. When problems develop you may have restrictions or air intrusion that lead to hard starts or shutdowns under load.

How often should it be inspected?

How often should fuel be polished?

Fuel tanks are inspected for leaks, water accumulation, sediment buildup and proper ventilation every quarter during PM1 inspections. Annual fuel polishing during PM2 service removes accumulated water and contaminants maintaining fuel quality for reliable operation.

Environmental Considerations: Underground tanks in high water table areas experience more water intrusion requiring more frequent inspection. Tanks exposed to large temperature swings accumulate more condensation. Biodiesel fuel supports microbial growth requiring biocide treatment. Tanks near saltwater experience accelerated external corrosion of steel components.

• Water in Fuel Samples: Free water visible in fuel or filter bowls indicating tank condensation or groundwater intrusion.
• Microbial Growth in Tank: Dark stringy material in fuel indicating biological contamination from bacteria or fungus growth.
• Sediment in Tank Bottom: Visible accumulation of rust, dirt or degraded fuel particles settling in tank.
• Fuel Smells Rancid: Off odor indicating degraded fuel from age or biological contamination.
• Tank Leaks or Corrosion: Visible fuel seepage, rust perforation, or structural deterioration of tank material.

“My fuel tank is only a few years old—does it really need inspection and maintenance?”

Absolutely. Fuel contamination happens in all tanks regardless of age. Daily temperature cycling causes moisture in tank air space to condense on cool tank walls dripping into fuel. Within months this creates sufficient water for microbial growth. Bacteria and fungus feed on diesel fuel creating dark slimy biomass that plugs filters and corrodes fuel system components from acidic byproducts. Rust particles from steel tanks accumulate even in new tanks. Sediment from fuel delivery settles in tank bottom. Without regular inspection and fuel polishing this contamination reaches your engine during emergency operation causing shutdown exactly when you need power most. Annual fuel polishing and tank cleaning are essential preventive maintenance.