The Spirit of '76 (1990) on Netflix

It's 2176 in America, a time when all records of its history have been lost and the world is in near collapse. Just before Dr. Von Mobil dies, he the last person who lived in the era when those records were still in existence, he tells the authorities that the key to regaining America's past glory and possibly save the world from collapse can be found in 1776, the founding of the nation. The authorities co-opt Adam-11 to lead the mission to 1776 using his time machine. Adam-11 only wants to use his time machine to travel to the paradise land of Ick Icky Beach, beaches which don't exist in 2176. Adam-11 agrees when he meets his fellow time traveler, the beautiful but officious Chanel-6, and when the authorities promise him enough fuel post-mission to travel to Ick Icky Beach. The third member of the team is the equally as officious Heinz-57. The three only have twelve hours to retrieve such information as what is contained in the Constitution, or else they risk never returning to 2176, with the future world survival in jeopardy. However, the time machine ends up missing its mark by two hundred years, and they unknowingly land in 1976 instead. There, they are assisted by a couple of teen-aged slackers named Chris Johnson and Tommy Sears. Chris and Tommy believe that Adam-11, Chanel-6 and Heinz-57 are indeed from the future and help them if only to thwart the plans of high school science geek Rodney Snodgrass, who wants to use "the aliens" as his science fair project. The CIA are also aware of the aliens and are on their tail. As the three time travelers experience 1976 culture and its mores - thinking it all will save the planet in 2176 - they try to elude the police and the CIA. But their mission and their return to 2176 may be in further jeopardy by Rodney, who will do anything to win the science fair.