Republican Clark Durant has raised a hefty $750,000 in the six weeks since he entered the Senate race in Michigan, his campaign announced Tuesday.

"I am truly humbled and encouraged by the outpouring of support," Durant said in a statement. "There is momentum building to shake up Washington. Our supporters are sending a strong message that they want the American way, not the Washington way."

Durant is running in a primary against former Rep. Pete Hoekstra (R-Mich.), who is considered the favorite to take on Sen. Debbie Stabenow (D-Mich.). Because of his experience raising money for the Cornerstone Schools, Christian charter schools he helped found in Detroit, Durant was expected to have the connections to be a strong fundraiser. He is also personally wealthy and could have contributed to his campaign.

Hoekstra is known as a strong campaigner but a weak fundraiser. Two weeks ago his campaign predicted he would bring in between $400,000 and $500,000 in the three-month fundraising quarter that started in July. He has yet to announce his fundraising figures, but campaign manager John Yob tweeted Tuesday afternoon that he had outraised Durant.

Durant lacks the name recognition Hoekstra built during his unsuccessful 2010 run for governor, and the former lawmaker led Durant by 41 percent to 3 percent among Republican voters in a late September poll. But if Durant continues his strong fundraising pace he could make things interesting in the Republican primary.

If Durant makes the race competitive he could hurt Hoekstra's chances in the general election by forcing him to spend money in the primary rather than save his resources for Stabenow, who had more than $4 million in the bank at the end of last quarter.

—This post was updated at 1:12 p.m.