The nation's major retailers yesterday reported stagnant sales in February as a spending spree on cars and homes siphoned off consumer funds for general merchandise.

"The February sales were pretty mediocre, and a continuation of the sluggish trend that has persisted for the last six months," said Jeffrey Edelman, a retail analyst at Dean Witter Reynolds in New York. "Retail sales and consumer spending generally mirror economic activity, which has been slow."

Edelman noted that "lower interest rates are propelling consumers to purchase cars and houses, which take a big bite out of personal income and increase already high installment-debt rates."

Sears, Roebuck and Co., the largest retailer and a bellwether for the industry, reported sales for the four weeks that ended Saturday fell 2 percent from the same period a year ago, to $1.76 billion from $1.79 billion.

Because Sears is a giant merchandiser of durable goods, analysts said the retailer's lackluster performance reflected poor consumer interest in big-ticket items such as appliances.

"There's been no real enthusiasm on the part of the consumer to go out and buy general merchandise since Christmas," said Monroe Greenstein, a retail analyst at Bear, Stearns & Co. in New York.

K mart Corp., the No. 2 retailer, had a 1.4 percent increase in February sales, to $1.36 billion from $1.29 billion in the same period last year. "A cautious consumer and unfavorable weather conditions teamed up in February to hold down sales somewhat," K mart Chairman Bernard M. Fauber said.

But Joanne Legomsky, an analyst at Standard & Poor's Corp. in New York, said February -- the first month of the fiscal year for most retailers -- traditionally is a slack month for retailers, and weather conditions should not be considered a major factor in the results.

Analysts pointed out that most retailers offered fewer markdowns last month than in February 1985, when a poor Christmas season left the industry with bulging inventories.

"Even though 1986 is not off to a particularly strong start, too much should not be made out of February. It's a very small month," said Jeffrey Feiner, an analyst at Merrill Lynch in New York. "We still expect to see a good Easter season, which accounts for 50 to 75 percent of sales in the first quarter."

Spending was adversely affected by Americans' high levels of installment debt, the Merrill Lynch retail specialist said. That prevents consumers from buying big-ticket goods and affects lower- and middle-income consumers the most. And that was reflected, in particular, in the poor sales at Sears and K mart, he said.

"A high level of debt is going to temper sales a little bit, but I don't think it's the only cause for the sluggish sales we've seen," Edelman said. In addition to the high levels of debt, Greenstein cited Americans' low levels of savings as a reason they are reluctant to spend.

"What we're seeing is a retrenchment after the big Christmas buying period," said Standard & Poor's Legomsky. "I don't think the pullback is permanent or presages a slowdown in consumer spending."

Third-ranked J. C. Penney Co. announced its February sales rose 7.4 percent to $741 million from $690 million in the same month last year. Penney said its sales gained momentum as the month progressed.

In fourth place, Federated Department Stores -- the parent of Bloomingdale's and I. Magnin -- posted a 5.1 percent upturn in February sales, to $657.2 million from $625.3 million a year earlier.

Dayton-Hudson Corp., the No. 5 retailer, reported its sales climbed 14.2 percent to $542.2 million from $474.6 million last February. The retailer cited "good response to promotional events during the month, which suggests that customers continue to be very value conscious."

Wal-mart Stores Inc., the sixth-largest retailer last year, but now threatening to overtake Dayton-Hudson, said its sales spurted 42 percent to $616 million from $435 million, but sales for stores open more than a year rose a more modest 19 percent.

F. W. Woolworth Co., ranked seventh, said its foreign and domestic sales rose 8.9 percent to $371 million from $341 million. Woolworth said its net income for the three months that ended Jan. 31 totaled $106 million ($3.29 a share) compared with $92 million ($2.91). Sales for the period rose 5.3 percent to $1.85 billion from $1.76 billion. For the year, Woolworth said its net income rose 26 percent to $177 million ($5.50) from $141 million ($4.45). Twelve-month sales rose 3.9 percent to $5.96 billion from $5.74 billion.

May Department Stores Co., the parent of the Hecht Co. and the nation's eight-largest general merchandise chain, said its sales rose 9.8 percent.

No. 9 Montgomery Ward & Co. said its sales fell 6 percent to $241.3 million from $256.7 million a year earlier.

Allied Stores Corp., the New York group that owns Garfinckel's, Brooks Bros., Ann Taylor and other stores, reported a 5.1 percent rise in sales to $264.9 million from $251.9 million a year ago.

Associated Dry Goods Corp., the New York-based parent of Lord & Taylor and Caldor discount stores, said its sales increased 4.2 percent to $256.4 million from $246 million last February.

Zayre Corp., of Framingham, Mass., said its sales climbed 41.3 percent to $260.2 million from $184.1 million in February last year.