For Walbro Corp., a maker of fuel-supply systems, Korea has been a mixed bag.

On one hand, the company wants to scale back its investment in the three-year-old Korean Automotive Fuel Systems, a joint venture with Daewoo Precision Industries to build fuel pumps and reservoirs for Daewoo.

"The operation became more expensive as the won became devalued," says Bert Althaver, Walbro chairman and chief executive who recently announced his retirement. "It was not something we could live with."

Walbro in January began producing plastic fuel tanks as a wholly-owned plant also in Korea. While auto sales are down in the region, Walbro's tanks are installed on the new Matiz built by Daewoo.

"That's been in our favor because it's a less-expensive car," says Mr. Althaver says. "We are continuing to operate as we had planned, but it's a challenge."

The range of experiences makes it difficult for anyone to generalize about globalization. For instance, Walbro's expansion into Europe three years ago has brought it new business not only in that region but also in the U.S.

"Globalization is the right direction. You will always have markets turning negative and ones that turn positive," Mr. Althaver says. "For every problem like Korea, you will find a positive in another part of the world."