Ameron International Corp. said Thursday that the continued slow economy contributed to a 42 percent drop in fiscal second quarter profit, but the results beat Wall Street expectations and its stock gushed.

The Pasadena water transmission line maker reported net income of $9.4 million ($1.03 per share) for the quarter ended May 31, compared with net income of $16.3 million ($1.78) a year ago.

Revenue fell 17 percent to $133 million, as a decline in public works spending meant fewer orders for the company’s products.

Analysts surveyed by Thomson Reuters on average had expected earnings of 46 cents per share on revenue of more than $145 million.

The company warned it may revise its previous 2009 earnings guidance of between $3 and $3.50 per share. Analysts expected full-year earnings of only $2.53 per share.

“The company will continue to strive to reduce costs to support profitability on lower sales,” Chief Executive James S. Marlen said in a statement. “Ameron’s businesses remain well-positioned to benefit from higher infrastructure spending, both private and public, when conditions improve.”

Ameron shares were up $4.08, or 8 percent, to $54.89 in midday trading on the New York Stock Exchange.