Engine & Mechanical

The Fuel System and Pump

IntermediateThe Giulia Spider's fuel system from tank to carburettor — checking delivery and leaks, dealing with a dirty tank, and what modern ethanol petrol means for an old car.

The Giulia Spider's fuel system is simple, but sixty years and modern petrol bring their own considerations — worth a look when buying, and worth keeping on top of in ownership.

From tank to carburettor

Fuel travels from the tank, through the lines and a filter, via the fuel pump to the carburettor — the single carb of the Normale or the twin Webers of the Veloce. It is a straightforward system with few surprises.

What to check

  • Fuel delivery: the engine should start promptly and run cleanly, without starvation — hesitation or cutting out under load points to a tired pump, a blocked filter, or dirt in the tank.
  • Leaks and smell: any smell of petrol, or damp lines and unions, must be addressed. A fuel leak on a hot classic is dangerous. Check the flexible hoses, which perish with age.
  • The tank: old tanks rust internally and shed debris that blocks filters and jets. A car that keeps fouling its carburation may have a dirty tank.

Ethanol and modern petrol

Modern ethanol-blended petrol (E5, and increasingly E10) can attack old rubber fuel lines, seals and some carburettor parts, and encourage corrosion in the tank. Many owners fit ethanol-compatible fuel hoses and are careful which fuel they use. If a car has stood, stale fuel and gummed carburettors are common — and usually cleanable.

What it means

Fuel-system work is generally cheap and routine — hoses, a filter, a pump overhaul, a carburettor clean — but a fuel leak is a safety priority, so treat any sign of one seriously rather than later.