Despite improved U.S. hiring last month, most Wall Street economists still expect the Federal Reserve to do more to stimulate growth this year, with the majority looking for action as soon as September.

The median of forecasts from a Reuters poll of 17 primary dealers - the large financial institutions that do business directly with the Fed - showed a 63 percent chance the central bank will for the third time expand its balance sheet via large-scale bond purchases.

If the Fed does act, 13 said they thought it would do so at its next policy meeting in September, up from eight in a July 6 Reuters poll of 16 dealers.

There are 21 U.S. primary dealers.

Friday's poll was conducted after a government report showed employers added 163,000 new jobs in July, the most in five months.

That was above the 100,000-job gain economists expected and prompted some dealers to reduce slightly their expectations for a new round of purchases, known as quantitative easing, or QE3.