SAN FRANCISCO - Engineering and construction company Foster Wheeler is learning how to grow more through mergers and acquisitions, but must shed its careful approach first, its chief executive said on Thursday.

It's hard for us culturally because we just tend to be conservative, CEO Ray Milchovich told investors at the D.A. Davidson Engineering and Construction Conference in San Francisco.

Foster Wheeler shares, up more than 5 percent after being upgraded by Goldman Sachs on expectations of the company winning Australian liquefied natural gas work, shed some gains but were still 4 percent higher at $34.35 in early afternoon trading on Nasdaq.

In the past year and a half, Foster Wheeler has made three acquisitions for undisclosed prices, including the offshore engineering division of OPE Holdings in April to increase its capabilities in building for oil and gas production.

As for Foster Wheeler's operations, Milchovich said he was happy with the profit margins on new work being booked by both its engineering unit and its power plant equipment unit, although the market for the latter remained weak. (Reporting by Braden Reddall; Editing by Tim Dobbyn)