Wall Street pros believe a fall 2013 tapering of government bond purchases by the Federal Reserve is already priced into the markets, a new CNBC survey reveals.

On average, the respondents predicted Fed easing will commence in October, and that its current monthly pace of $85 billion in government bond purchases will be trimmed by $19 billion.

Most of the 50 economists, strategists and fund managers surveyed believe the impact of tapering is already baked into the Treasury and mortgage markets. But only a slim majority — 58 percent — said the impact is priced into the stock market, which CNBC said suggests that stocks could go lower when the Fed actually cuts back.

Editor's Note: Economist Unapologetically Calls Out Bernanke, Obama for Mishandling Economy. See What They Did

Some Wall Street types would like the Fed to act sooner and cut more decisively.

"The problems holding back economic growth are not monetary in nature and the risk of deflation is very low," wrote John Ryding of RDQ. "The Fed should taper more quickly and exit from zero rates. It won't, however!"

The CNBC survey respondents are becoming a bit more pessimistic in their growth outlooks. They lowered their 2013 gross domestic product (GDP) growth estimates below 2 percent for the first time this year, to 1.9 percent from an average 2.1 percent in June and 2.6 percent in January.

However, those surveyed ranked the probability of a fresh recession very low, although it inched up to 16.2 percent, and said the biggest threat to the recovery is tax and regulatory policy (30 percent) and slow job growth (22 percent).

MarketWatch reported economists it contacted are debating whether the Fed will taper in September or December.

Many Fed watchers believe the central bank will not tip its hand when it releases a much-anticipated statement on Wednesday and will not insert forward guidance about tapering, MarketWatch said.

"When push comes to shove, I expect an ambiguous message," stated Michael Hanson, U.S. economist at Bank of America Merrill Lynch.

The government's initial estimate of second quarter 2013 GDP gross is expected to show the economy slowed down to a 1 percent annualized growth rate from a 1.8 percent rate in the first three months of the year, according to MarketWatch.

Editor's Note: Economist Unapologetically Calls Out Bernanke, Obama for Mishandling Economy. See What They Did