The Navy is checking repair records on 300 jet engines after discovering that an error-prone mechanic was leaving critical parts out of gearboxes, a spokesman said yesterday.

But a Florida man who identified himself to a newspaper as the mechanic involved said the military is trying to make him a scapegoat.

Navy spokesman Lt. Ken Ross said since August 1986, there have been four incidents of engine seizures "due to an incorrectly assembled gearbox on the J52" jet engine that is used on several key Navy planes.

An engineering review of the unusual failures revealed that all four engines had been serviced by the same mechanic, a civilian employed at the Navy Depot in Jacksonville, Fla., Ross said.

"His performance was not up to snuff. And they found these four incidents with an amazing coincidence," Ross said. "There is a possibility that 300 engines could be affected."

Ross did not identify the mechanic. But the Florida Times-Union in Jacksonville reported in today's editions that he was identified in a letter of reprimand as Warren K. Woods.

Ross said the mechanic involved worked at the depot from 1981 until his certification was revoked in March 1986. Woods told the newspaper he was facing disciplinary action that could lead to dismissal.

Woods said that Navy officials, embarrassed by their failure to implement a more stringent quality-control program, are blaming him. He denied he was responsible for the errors.

"I know my work. And I know that I never left any parts off," he said.

The engines are used for TA4 trainers, the A6 Intruder attack plane, the KA6D tanker and the EA6B electronic warfare plane, Ross said.