NEW HAVEN — National Republicans are stepping up efforts in the congressional race to represent Connecticut’s Gold Coast, trying to recapture a seat the party held for decades before Democratic Representative Jim Himes was elected four years ago.

Himes is running against Republican Steve Obsitnik, recently named a ‘‘young gun’’ by the National Republican Congressional Committee that identified him as a strong contender. Obsitnik, 45, a former naval officer who lives in Westport, has received $4,000 from House Speaker John Boehner and another $10,000 from Boehner’s political action committee.