Charles Lollar (AP)

Republican hopeful Charles Lollar is preparing to launch his Maryland gubernatorial campaign in the first week of September with a three-day bus tour and a push for donations that he’s calling a “money bomb.”

Lollar, a Charles County businessman and Marine Corps Reserve officer, shared his plans for his “all-important announcement” in an e-mail to supporters Thursday night.

“After months of prayer and consideration, we have determined to take the next step in our public service to Maryland,” Lollar said in the email from him and his wife.

Lollar told The Post on Friday that the bus tour will start Sept. 3.

The “money bomb” is scheduled for Sept. 5. Lollar is asking all supporters to make a campaign contribution of some size on that day.

Lollar, who ran unsuccessfully for Congress in 2010, will join what is shaping up to be a competitive GOP primary in the race to replace Gov. Martin O’Malley (D), who is term-limited.

Harford County Executive David R. Craig (R) and Del. Ronald A. George (R-Anne Arundel) have announced gubernatorial bids, and several other Republicans are eyeing the race, including Michael Steele, the former Republican National Committee chairman, and Larry Hogan, leader of Change Maryland, a grass-roots group.

Maryland has had only one GOP governor in the past generation: Robert L. Ehrlich Jr. , who was defeated by O’Malley in 2006 after serving a single term.