FORD 1999 F-550 v.1 - Manual (Page 171)

4. Make the final connection of the negative (-) cable to an exposed
metal part of the stalled vehicle’s engine, away from the battery and the
carburetor.
The preferred locations of an exposed metal part (to ground the circuit)
are the alternator mounting brackets or an engine lifting eye. Do not
use fuel lines, engine rocker covers or the intake manifold as grounding
points.
Do not connect the end of the second cable to the negative (-)
terminal of the battery to be jumped. A spark may cause an
explosion of the gases that surround the battery.
5. Be sure that the cables are clear of fan blades, belts and other moving
parts of both engines.
Jump starting
1. Start the engine of the booster vehicle and run the engine at
moderately increased speed.
2. Start the engine of the disabled vehicle.
3. Once the disabled vehicle has been started, run both engines for a
further three minutes before disconnecting the jumper cables.
Roadside emergencies
171