WASHINGTON — The clock is ticking on implementation of the Affordable Care Act (ACA), with less than two months to go until the October 1 deadline for state health insurance exchanges to be open for ­business.

With the Obama presidency riding in part on the law’s outcome, the White House has established a team to entice uninsured Americans to get health coverage.

The team has been coordinating the effort with retail pharmacies as well as insurers, state governments and hospitals. Chief communications adviser Tara McGuinness has a spreadsheet showing some of the estimated 8,000 Walgreen Co. stores that, in conjunction with Blue Cross and Blue Shield, are disseminating information about the statute.

The team is focused on the 2.7 million uninsured Americans, ages 18 to 34, who are generally healthy. The ACA’s success rests in part on that demographic because, if relatively healthy Millennials purchase coverage, their premiums will help offset the costs of insuring older and sicker people.

The conventional industry approach to risk — increasing prices for sicker customers — is prohibited under the law, so getting young, healthy Americans to buy insurance is ­essential.

Amid reports that the ACA has already led restaurants to cut back on hiring and hours, David Vandivier, chief of staff of the Council of Economic Advisers, posted a blog on the White House website contending that the opposite was true.

“In reality … restaurants have had the fastest job growth of any industry in the retail and food services sector since the Affordable Care Act was signed into law,” he wrote. “Furthermore, workers in the restaurant industry have seen their average weekly hours increase since the ACA was signed, contrary to the notion that there has been a widespread shift to part-time hours.”

Across the private sector, he added, the length of the average work week for production and nonsupervisory employees has returned to its level at the start of the Great Recession.

Data “strongly suggest that the Affordable Care Act has not constrained growth in hiring or work hours,” said Vandivier. “So what is the ACA doing? It’s slowing the growth rate of health care costs for consumers, creating new incentives for providers to raise the quality of care, and adding new transparency and accountability in the insurance marketplace — all steps that help the economy.”

But Hugh Raetzsch Jr., chairman of the American Wholesale Marketers Association, said in testimony submitted to the Senate Small Business Committee that the ACA is posing serious challenges for some convenience industry wholesalers, many of whom are small, family-operated businesses.

Raetzsch, president of Lyons Specialty Co. of Port Allen, La., said his company may be forced to reconsider its policy of providing insurance to full-time employees as a result of uncertainties, complexities and additional costs stemming from the act.

He said that Lyons, which serves about 550 convenience store retailers in Louisiana and Mississippi, pays 75% of the premium for its full-time workforce of 85 professional and hourly employees and that about half of them take advantage of the opportunity.

The unknowns of the ACA “have been recounted time and again, and they continue to complicate the issue for us,” he said, pointing to the uncertain cost of compliance and questions surrounding the details of what companies like Lyons need to do to comply. “I promise you, we do not have office personnel sitting around and waiting for more work; nor are they skilled in this area. Must we hire a consultant to manage this? What will that cost?”

Republicans, meanwhile, continued to try to thwart the health care reform law’s rollout. Senate Republicans sent a letter to majority leader Harry Reid of Nevada threatening to reject any spending bill to keep the government operating after September 30 if it devotes any money to the act. Signers included the No. 2 and No. 3 Republican senators, John Cornyn of Texas and John Thune of South Dakota, as well as Marco Rubio of Florida.

The letter, drafted by Sens. Mike Lee of Utah, Ted Cruz of Texas and Rand Paul of Kentucky, states: “If Democrats will not agree with Republicans that Obamacare must be repealed, perhaps they can at least agree with the president that the law cannot be implemented as written. If the administration will not enforce the law as written, then the American people should not be forced to fund it.”

For its part, the administration enlisted Jennifer Hudson, Amy Poehler, Aisha Tyler and representatives for Oprah Winfrey and Jon Bon Jovi to promote the statute. Tyler told David Letterman on his show that Obama was trying to help people understand the ACA “and know that young people can get insurance where they couldn’t afford it before.”