The White House's man responsible for curing the Obamacare website tech disaster vowed Friday that the HealthCare.gov site is "fixable," and "will operate smoothly for the vast majority of users" by the end of November.
"It's going to take a lot of work, and some time, but there's a clear path," Jeff Zients told reporters on a conference call about the troubled health insurance marketplace site, whose many problems have prevented many people from enrolling in coverage. "Each week, HealthCare.gov will get faster and better."
"Let me be clear: HealthCare.gov is fixable," said Zients, who announced a new "general contractor" will oversee the aggressive push to repair that site.
That contractor is UnitedHealth Group subsidiary QSSI, which has already built the site's federal data hub, a core function that unlike the rest of HealthCare.gov is said to be working as designed.
QSSI's appointment is a clear slap in the face both to CGI Federal, which was the primary contractor in building HealthCare.gov, and to the site's operator, the federal Centers of Medicare and Medicaid Services. CMS was responsible for making sure the components built by separate contractors worked together.
(Read more: What did Sebelius know, and when?)
"They are familiar with the complexity of the system . . . they have the skills and expertise to address these problems right now," said CMS spokeswoman Julie Bataille about QSSI.
Bataille's agency has been faulted for doing end-to-end testing of HealthCare.gov just two weeks—or less—before its Oct. 1 launch, and for launching the site even after tests revealed serious software problems that became even worse with thousands of actual visitors.
Bataille promised that the repairs would allow anyone who wished to apply and enroll for insurance from that site by Dec. 15, the deadline for coverage beginning Jan. 1
Zients said a team of "leading" government and private managers and programmers have assembled a "punch list" of "dozens" of issues they have identified over the past week with both the performance and functionality of the federal website, which is selling insurance to the residents of the 36 states not operating their own Obamacare health exchanges.
"There will be a relentless focus on speed and execution to work through that punch list," Zients said. "The general contractor will prioritize the needed fixes, and make sure they get done."
"Each week, the site will get better . . . by the end of November, HealthCare.gov will work smoothly for the vast majority of users."
(Read more: Insurers pow-wow at White House about Obamacare mess)
Providing quality enrollment data to insurers from those registering through the site is a priority, Zients said. Insurers have said much of that data they receive is corrupted or questionable in some way, with spouses being listed as children, or multiple enrollments being sent for one person, and enrollments being repeatedly cancelled and resent from HealthCare.gov.
On Thursday, CMS spokeswoman Bataille had claimed "this is a fairly isolated issue" and "we have been told it is getting better." But Zients made clear that it was not only a widespread problem, but a top priority to get fixed.
Another issue of questionable data was disclosed Friday afternoon by Washington State, which revealed that 8,000 enrollees and applicants on its state-run Obamacare marketplace were told they were eligible for higher tax credits to offset the cost of their insurance than they actually qualified for. Washington said that in some cases its exchanges was transmitting those applicants' monthly incomes to the federal data hub — which verifies subsidy eligibility — as opposed to annual incomes, which resulted in the erroneously high subsidy calculations. The problem has since been fixed, and Washington is in the process of notifying all of the affected people to give them the correct tax credit amounts.
Zients, the former acting director of the federal Office of Management and Budget, was appointed last week by the White House to oversee the repair effort. In January, he is set to become President Barack Obama's director of the National Economic Council.
His interim appointment came as HHS was blasted both by Republicans and Democrats for its handling of the site, which is a key component of Obama's signature health-care reform law.
On Friday, Zients said "the high volume" of visitors at the site's launch created problems at the front end—the interface that visitors encountered when they tried to log on to the site and create an account, which is a required first step before shopping for insurance coverage. That volume also revealed problems on the "back end," Zients said, referring to the part of the site that processes enrollments and sends them to individual insurers whose plans are on sale at HealthCare.gov.
At its worse, Zients said, just 3 in 10 visitors to the site were able to get through the application process. That percentage has significantly improved, he said.
But Bataille declined, again, to release enrollment figures from the site, saying those numbers would be released next month. The federal site's refusal to release enrollment data stands in stark contrast to many state-run health exchanges, which are releasing that information, and whose performance has been on the whole much smoother than HealthCare.gov.
(Read more: Meet the GOP's Obamacare "expert)
She and Zients also refused, in response to several questions, to identify the managers and programmers who were part of the "tech surge" to identify and correct HealthCare.gov's problems.
"We need to have their heads down, focused on this issue, and getting things off that checklist," Zients said.
Bataille emphasized that the site is currently enrolling people, and that by Dec. 15 anyone who is eligible will be able to enroll in coverage starting Jan. 1. People will have until March 31 to enroll in coverage without incurring a tax penalty.
Under Obamacare, nearly all Americans are required to obtain health insurance by March 31 or face that penalty. Most people have insurance through their employers, or the government-run Medicare and Medicaid programs—and the government-run exchanges like HealthCare.gov were set up to sell coverage to the tens of millions of people who don't have insurance.
—By CNBC's Dan Mangan. Follow him on Twitter @_DanMangan.