* Foreigners' selling may bottom out
* Short-term rebound may be possible, but mid-term mood shaky
* Obama jobs speech awaited for clues on U.S. economy
* Machinery stocks weaker after machine orders data
By Ayai Tomisawa
TOKYO, Sept 8 (Reuters) - The Nikkei stock average on Thursday pulled further away from a six-month low hit this week, helped by hopes of an improvement in Europe's debt situation but the rise was tempered by continuing uncertainty about the U.S. economic outlook.
It was a second straight day of gains for the benchmark average, one which also yielded signs that foreigners are turning less bearish towards the market.
Nine foreign securities houses placed net buy orders, albeit by a slim margin, before the start of trade on Thursday, following 29 trading sessions of net selling, while data also showed the amount of foreign net selling shrank sharply last week from the previous week.
"It is likely that the selling trend may turn around, and a short-term rebound is expected," said Eiji Kinouchi, chief technical analyst at Daiwa Securities Capital Markets.
Investors are looking ahead to U.S. President Barack Obama's speech to Congress on Thursday after the U.S. market close, to hear his administration's plans to boost the economy.
U.S. Federal Reserve Chairman Ben Bernanke will also speak on the U.S. economic outlook later Thursday, after the Fed's Beige Book summary of regional economies showed growth slowed in some U.S. regions during May.
"Investors are still wary. It won't be easy to convince investors that there will be a turnaround with the current state of the U.S. economy. What about its massive deficit and what about debt problems in Europe?" said Fujio Ando, general manager at Chibagin Asset Management.
"Even though the European Central Bank is buying sovereign bonds of problematic countries in the euro-zone, this sort of measure is only a temporary solution."
The benchmark Nikkei climbed 0.3 percent in thin trade to 8,793.12, its second day of gains. On Tuesday it fell as far as 8,588, its lowest level since March 15, when stocks were sold off in the wake of the earthquake and tsunami.
The broader Topix index added 0.5 percent to 757.41.
That followed a 2 percent bounce for Wall Street on Wednesday after Germany's top court smoothed the way for Berlin's participation in bailouts that could ease Europe's debt crisis.
But shares of machinery makers such as industrial robot maker Fanuc Corp weakened after Japan's core machinery orders fell in July at twice the pace economists' expected.
Fanuc ended down 3.4 percent at 11,610 yen and construction machinery maker Komatsu shed 1.9 percent to 1,881 yen after the data raised concerns about the outlook for corporate capital investment although the concerns were not enough to push other sectors lower.
Telecommunications firm Softbank was fell 1.7 percent to 2,722 yen after Citigroup lowered its rating to "hold" from "buy", saying that growth in earnings is likely to be limited for the next two years as the company increases capital spending.
But Sumco , the world's No.2 supplier of silicon wafers used to make chips, surged 2.6 percent to 877 yen after Credit Suisse raised its rating to "neutral" from "underperform", saying its poor earnings estimate and falling DRAM demand have been priced in.
Inpex rose 4.5 percent to 492,500 yen and Japan Petroleum Exploration gained 3.3 percent to 3,080 after oil climbed by more than $3 to a five-week high on Wednesday.
Some 1.46 billion shares traded on the main board, compared to last week's average daily trading volume of 1.81 billion shares.
Weekly data showed foreigners were net sellers of Japanese stocks to the tune of 87.7 billion yen in the week ending Sept 3, the sixth straight week of selling. That was the longest such streak since May-June 2010, but last week's net sales were much lower than the previous week's 338 billion yen. (Additional reporting by Lisa Twaronite; Editing by Edwina Gibbs)