* Soybeans and corn set for weekly gains
* Brazil soy exports seen picking up after delays (Adds quote, updates prices)
By Nigel Hunt
LONDON, March 3 (Reuters) - Chicago soybean futures were lower on Friday as the market's focus returned to an improving crop outlook in South America, halting a run-up driven partly by shipment delays in Brazil.
Corn also eased, though it was set for a weekly gain on expectations of higher ethanol production in the United States, while wheat dipped for a second session.
The Chicago Board of Trade's most-active soybean contract was down 0.2 percent at $10.35-1/2 a bushel by 1155 GMT but remained on track for a weekly gain of 1.1 percent after two weeks of losses.
At least 11 ships are facing delays in loading soybeans at Brazil's northern ports after rains washed out roads and disrupted the progress of trucks carrying beans from the centre-west region, Brazilian officials said on Thursday.
"The export flow may pick up again next week, provided weather conditions have allowed enough road repairs to take place," said Tobin Gorey, director of agricultural strategy at Commonwealth Bank of Australia.
Soybeans came under pressure as estimates of Brazil's soy harvest continued to rise. Private analytics firm Informa Economics raised its forecast of Brazil's crop to a record 108 million tonnes, trade sources said, up nearly 2 million tonnes from its previous estimate.
The figure is above the last monthly estimate from Brazil's government agency Conab, which put the crop at 105.6 million tonnes, and the U.S. Department of Agriculture's figure of 104 million tonnes.
Growing conditions in Argentina's main soy belt were helped over the previous seven days by showers in areas that had suffered from a lack of ground moisture, the Buenos Aires Grains exchange said in its weekly crop report on Thursday.
Soybean and corn futures rose earlier this week, supported in part by reports of potential changes to U.S. biofuel policy to boost production. Corn is the primary U.S. feedstock for ethanol and soyoil is used in biodiesel.
"The biofuel rumours in the U.S. have thrown uncertainty and confusion back into the market. They come as U.S. farmers are deciding which spring crops to grow," said David Sheppard, managing director at UK merchant Gleadell.
CBOT's most-active corn contract was down 0.3 percent at $3.78-1/2 a bushel but on track for a 4 percent weekly gain.
Wheat prices eased, weighed partly by an improving crop outlook in the Black Sea region.
CBOT's most active wheat contract was down 0.8 percent at $4.49 a bushel while May milling wheat futures in Paris fell 0.7 percent to $176 a tonne. (Additional reporting by Naveen Thukral in Singapore; Editing by Biju Dwarakanath and David Goodman)