The engines involved in the recall were used on Sears, Husqvarna and Bad Boy riding mowers, the U.S. Consumer Product Safety Commission said.
Wiring on the engines was incorrectly routed, leaving them vulnerable to wear that could disconnect the shut-off mechanism, allowing the engine to continue operating even with the key in the "OFF" position, the commission said.
The engines were included in Craftsman mowers sold at Sears, Husqvarna mowers sold at Home Depot and Bad Boy mowers sold at Tractor Supply Co.
The mowers were sold in February and March 2010 for between $1,500 and $3,500.
Consumers were advised to contact a Briggs & Stratton dealer and arrange for a free inspection.
Consumers can call 866-927-3349 for information.