A majority of young voters support Sen. Bernie Sanders Bernie SandersJacobin editor: Primarying Schumer would force him to fight Trump's SCOTUS nominee Trump campaign plays up Biden's skills ahead of Cleveland debate: 'He's actually quite good' Young voters backing Biden by 2:1 margin: poll MORE' (I-Vt.) decision to endorse former Vice President Joe Biden Joe BidenJoe Biden looks to expand election battleground into Trump country Trump puts Supreme Court fight at center of Ohio rally Special counsel investigating DeVos for potential Hatch Act violation: report MORE, according to a new Hill-HarrisX poll.

Sixty-two percent of voters 18 to 34 years old supported the Vermont senator's endorsement, while a little over a third opposed it.

Sanders' endorsement received majority support among voters overall (63 percent), and from Democrats (87 percent) and independents (59 percent).

Fifty-eight percent of Republican voters said they opposed the endorsement.

Younger voters have been a weak spot for Biden.

According to a CNN analysis of all Edison Research surveys conducted during the primaries, Biden took just 16 percent of the vote from Democratic primary voters under 30 years old, while Sanders received 65 percent of that vote.

A recent Morning Consult survey, however, did find that Biden's popularity among young voters had ticked up.

The Hill-HarrisX poll was conducted online among 958 registered voters between April 19 and 20. It has a margin of error of plus or minus 3.17 percentage points.

—Gabriela Schulte