Engine Driven Fuel Transfer Pumps.

Where there is no electrical supply and the volumes are too large for a battery pump — bulk transfer between tanks, emptying a tanker, filling a bowser, or moving fuel on remote sites.

They deliver flow rates that battery pumps cannot sustain, typically several hundred litres per minute depending on the unit.

Petrol engines are lighter, cheaper and easier to start in cold weather. Diesel engines are more economical over long running periods and avoid keeping petrol on a site that otherwise only stores diesel.

For occasional use, petrol is usually the practical choice. For regular extended running, diesel earns its keep.

Only if the pump is specifically rated for flammable liquids, with appropriate seals and materials. Most general-purpose engine pumps are not, and using one on petrol is a serious ignition risk.

Check the pump's stated compatibility rather than assuming it will handle any fuel.

Typically higher than electric transfer pumps, often four to six metres depending on the model, but the same principles apply — mount as close to the fuel level as practical and fit a foot valve.

Long suction runs add friction losses that reduce the effective lift considerably below the headline figure.

Most centrifugal engine-driven pumps need priming before first use and after the line has drained. Self-priming models handle this automatically but still need liquid in the pump body to start.

Running dry damages the seal, which is the most common failure on these pumps.

The engine is an ignition source, so siting matters — keep it upwind and well clear of vapour, and never refuel the pump's own tank while it is running or hot.

Exhaust fumes mean they must not be run in enclosed spaces, which is easily overlooked when working inside a bunded compound.