Organizers of Sunday's Marine Corps Marathon said that the casualties at last weekend's New York City Marathon, in which one runner died, 200 were hospitalized and almost 1,200 required medical treatment, would not cause any alteration in their plans.

"We haven't changed anything we normally do," race director Capt. Chris Moody said yesterday during a press conference at the Touchdown Club to preview the ninth running of the 26.2-mile race through Arlington and downtown Washington.

"The weather calls for 60 degrees this weekend. New York was in the 70s. If it looks like it will be warmer, we will double the amount of ice from the 3,500 pounds of ice that we already have."

A field of 11,761 runners from all 50 states and 40 nations is entered in the marathon, which is second in size only to New York in this country. The race, which begins at the Iwo Jima Memorial in Arlington at 9 a.m., will pass the Jefferson and Lincoln Memorials and the U.S. Capitol, before returning to the starting point.

In the past, the weather in Washington has varied for the marathon. Last year, temperatures climbed only into the mid-30s by the start of the race. Other years, the race has been run in rain and heat.

"We prepare all our medical personnel and equipment for the extremes of the weather," said Lt. Cmdr. William Moore of the Naval Medical Clinic, the medical coordinator for the race. "We have swimming pools at aid stations to immerse people. We have heaters at the stations. Last year, we didn't have heaters and it was 37 degrees.

"There is nothing we would do differently than we had planned because of the death up there (in New York). The difference between our coverage and theirs is that they don't treat their runners on the race site. We do. They don't have the field operations concept that we do."

Moore also emphasized, "If we see anyone on the course out of control, we'll pull them off the course. That's always been our policy."

Moore said that in 1982, his unit treated 600 runners, primarily with blisters and orthopedic problems. One runner was admitted to a hospital with a heart attack.

Last year, 560 runners were treated, about 150 of them for hypothermia, a condition of below-normal body temperature frequently experienced in cold weather. One runner was admitted to George Washington University Hospital with severe hypothermia; he was released four hours later.

The Marines call their marathon a "people's race," because while other large marathons lure elite runners with prize money and appearance fees, this race emphasizes the amateur aspect of road racing.

Although nearly 65 percent of the entrants are first-time marathoners, there are a number of veterans who are favored to win. Top-seeded runners include 1980 champion Cpl. Michael Hurd of Oxford, England; Robert Johnson of Hopkinton, Mass.; Jim Hage of Rockville, and Henry O'Connell of Kensington.

"I've run more marathons than any of the top runners," said O'Connell, whose best time in 10 marathons was 2:16 in Chicago last year. In 1981, O'Connell completed the Marine marathon in 2:28.

Sgt. Farley Simon, the first Marine to win the race, will not defend his 1983 title because he injured a groin muscle in a training run. Simon completed the race in 2:17:46, 1:16 slower than the course record set in 1981 by Dean Matthews.