More resorts are under threat, with the storm's course expected to take it past Puerto Vallarta and then on a direct course toward Cabo San Lucas on the tip of Baja California.
The center of the ferocious storm was forecast to remain just offshore south-western Mexico, with hurricane-strength winds reaching the coast.
Rhe Miami-based National Hurricane Center has warned that a light deviation from the projected track could steer the hurricane inland.
John packed maximum sustained winds of 215 kilometres an hour, which put it at category four, the second highest level on the Saffir-Simpson intensity scale. NHC forecasters said it could strengthen further.
Thousands evacuated
Hurricane-force winds extended outward up to 95 kilometres from the center, which was 135 kilometres west-southwest of the port city of Lazaro Cardenas at 2100 GMT. It was moving toward the northwest at 22 kilometres an hour.
Mexican authorities alerted residents along coastal areas of Michoacan and Jalisco to brace for possible hurricane conditions.
Forecasters projected the storm would eventually brush past the Baja California tip before veering westward toward the open Pacific waters.
Authorities in Jalisco ordered the evacuation of 8,000 people and urged others to board up their homes as the hurricane drenched much of the region.
Winds and rain propelled by the storm uprooted trees and caused mudslides in the seaside tourist resort of Acapulco.
The NHC warned that rainfall could cause "life-threatening flash floods and mudslides," and that "large and dangerous battering waves" should be expected in areas close to the hurricane's path.