UPDATE 1-Venezuela's Amuay refinery restarts delayed coker

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CARACAS, May 7 (Reuters) - Venezuela's 640,000 barrel per day Amuay refinery has restarted its delayed coker following planned maintenance on the unit, a refinery source told Reuters on Wednesday.

The source said the unit was operating at about 50 percent capacity and would be fully operation "by the weekend."

A PDVSA spokesman declined to comment, saying the company does not discuss routine maintenance. Sources last week told Reuters that Amuay's Distillation Unit No. 3 was also down for planned maintenance.

State oil company PDVSA this year is carrying out maintenance at a number of Amuay's units. Amuay and the neighboring 300,000 bpd Cardon refinery together form the giant Paraguana refining complex.

The twin have refineries have suffered repeated outages in recent months, many of them caused by power generation problems. (Reporting by Brian Ellsworth; Editing by John Picinich)