Marriott Corp. moved yesterday to make its second big acquisition in a month, offering to buy Gino's Inc. for $48.6 million.

Marriott, which last month agreed to buy Host International for about $130 million, announced plans to make a cash tender offer of $18 a share for all the 2.7 million shares of Gino's stock.

Gino's had been negotiating a merger with Marriott for months and immediately issued a statement saying its management "regarded favorably" the offer.

Gino's operates 313 fast-food outlets specializing in hamburgers and chicken, 43 Kentucky Fried Chicken outlets and 113 Rustler Steak Houses and had sales last year of $321 million.

In a year-end interview with The Washington Post last month, President J.W. (Bill) Marriott said the Bethesda chain was interested primarily in buying Gino's so it could expand its Roy Rogers operations.

Marriott said he favored converting about 150 of the Gino's stores into Roy Rogers as quickly as possible, selling off the unwanted locations and disposing of the chicken and steak restaurants.

Such a strategy would enable Roy Rogers to leapfrog several notches up the hamburger hierarchy and could make Marriott No. 5 in the burger business, said Charles Bernstein, chief editor of Nation's Restaurant News, the leading food service newspaper.

The combined sales volume of Roy Rogers and Gino's probably would rank just behind McDonald's, Burger King, Wendy's and Hardee's, which last week agreed to acquire Burger Chef, Bernstein said.

Because most of the Gino's locations are in the Northeast, Marriott's share of the fast-food business in this part of the country would be even greater. Marriott officials have estimated Roy Rogers could pick up $150 million to $175 million a year in volume from former Gino's sites. And since the older stores pay lower rent, they should be able to turn a profit more quickly than new ones.

"What Marriott has been doing as a corporation lately is just incredible," industry analyst Bernstein said. "The whole company is really moving."

He said finding sites for new fast food units "is the key to the battle. To get prime sites today is just about impossible."

Adding 50 new Roy Rogers units a year is Marriott's announced goal; converting 150 Gino's to Roy's would give the company three years' worth of growth in a much shorter time.

With the acquisition of Gino's and Host, which had sales of $357 million last year, plus its own internal growth, Marriott's corporate volume could come close to the $3 billion level this year, compared with $1.7 billion in its last reporting period.

Founded by former Baltimore Colts star Gino Marchetti, Gino's never made the first team in the fast-food league. Gino's sales have been stagnant for years and profits last year totaled only $4.4 million, less than 1.4 percent of sales.

Gino's stock jumped 62 1/2 cents a share to $17.50 after the Marriott offer, and Marriott's shares traded down slightly to $35.75.

In announcing the bid for Gino's, Marriott said it was interested only in a friendly takeover and would not make a tender offer unless Gino's directors accepted the offer. Officially Gino's was saying only that the board "will meet promptly to consider the offer."

Since the offer followed months of negotiations initiated by Gino's, rejection appears unlikely.

Marriott also said its offer was contingent upon being able to buy at least two-thirds of the Gino's stock.