Is it the service, as when the owner of the Bar B-Q Pit breaks off a conversation, leaps up and handles a customer’s bill?

Is it the loyalty that has kept people working for years for the same boss?

Is it just the taste of the product — bought fresh, cooked slow and served fast — that leads to requests to cater for 1,000 diners?

Is it the old-fashioned “American Graffiti” touches — car hops, blue soda fountain stools, juicy burgers, warm buns and homemade root beer?

If you answered “all of the above,” you’re right.

Quality food, attentive service and a smoky atmosphere of the good ol’ days have led Roy Mercado to success in running two of Merced’s iconic restaurants.

The 53-year-old immigrant from Mexico has parlayed all those ingredients for nearly two decades into places where Mercedians like to eat and to work.

By working long hours, treating employees and customers with respect, and demonstrating a commitment to Merced, Mercado has people lining up at the Bar B-Q Pit and HW Family Drive-In.

Plus thousands of meals a year catered for such groups as Harley-Davidson, a picnic for Merced city employees, MID workers at Lake McClure and, a week ago, the Sun-Star staff.

Mercado started in the restaurant business in the early ’80s with the Lyons chain in the Bay Area. First he was a dishwasher, steadily advancing until he became a troubleshooter for the chain. The company would send him to a place with problems, and he’d solve them and turn red ink into black.

In 1988 he started managing the Eagles Nest, a popular hangout (and now where Vinnie DeAngelo has revived his restaurant ).

“I came in with a Bay Area mentality,” Mercado recalled, sitting in the Bar B-Q Pit. “Giant burgers. That didn’t work, so I left everything intact.”

Including Jeremiah Terrones, who had worked at HW for the previous owner. “Roy let me learn how to manage the business,” Terrones said. “He helped me learn how to serve customers. He’s a very, very good person. Let me learn how to run the business.” He’s been at the window of the place on 16th Street for 17 years, 16 of them as manager.

Rick Osorio, a former Merced City Council member and owner of Osorio Financial Services, has helped Mercado with insurance, workers compensation, licensing and other issues. “It’s people like Roy who are going to make our county better,” he said. “He’s an amazing guy. He treats his employees really well.”

One-on-one, Mercado comes across as modest, almost shy. His businesses are making money, especially since the G Street underpass was finished; when drivers had to detour off G Street, he estimates he lost 20 percent of his revenue.

Mercado attributes success to “a solid foundation of customers, good food, good service, great value.”

Choice meats come from Sysco. They cook everything in the pit over almond wood. They make their own gravy from flour and milk.

“My philosophy?” he asks. “Eat good.”

His cook, Rick McGrary, stayed on after Mercado bought the Pit in 1992. Katie Robertson had left after Mercado sold the Pit a few years back. That owner “ran it into the ground,” said Osorio, and since Mercado owned the property he again took over. Robertson came back to work for him the next day and has been there nearly 20 years.He employs 30 people full time, 20 others part time.

Mercado also owns several properties in town, as well as a fleet of muscle cars.

One day he hopes to dial it all down. His daughter is a special-education teacher in Cupertino. His son has passed the law enforcement academy and is waiting for a job as a cop or deputy; he helps out at both restaurants. Their dad has been approached to open places north and south of Merced County but is content to stay where he is for now. He’s grooming people like Terrones to take over one day.

Meanwhile, “I enjoy every minute of what I do” he said. “I want to develop people so we can grow.”

Sitting in your car at HW — which several people on Yelp.com have said serves the best burgers and fries in town — you can almost sense the voices and feel the vibes from George Lucas’ 1973 hit, “American Graffiti,” set in the Valley.

Listen. You can almost hear Curt Henderson (Richard Dreyfuss) yelling: “Quick! Hang a right! Cut over to G Street! I just saw a vision!”

Executive Editor Mike Tharp can be reached at (209) 385-2456 or [email protected].