The Consumer Product Safety Commission said this is the second recall for the mowers. It involves mowers sold in the United States and Canada.
The pulley rubbing against the fuel tank is a potential fire hazard, the commission said.
The red and black mowers were sold at Toro dealers nationwide from January 2012 through April 2013 for between $7,700 and $8,700.
The mowers include the words "Toro," and "2000 Series" printed on the side and "Z Master Commercial" on the front.
Consumers were advised to stop using the mowers and contact a Toro dealer for a free repair.
Consumers can call 855-493-0090 for information.