Small engine manufacturer Briggs & Stratton Corp., founded in Milwaukee in 1908 by an inventor and an investor, on Monday filed for bankruptcy protection.

Briggs filed for Chapter 11 in the U.S. Bankruptcy Court for the Eastern District of Missouri. Under Chapter 11, a company and its creditors work out a reorganization plan that enables the business to continue to operate.

Briggs was the world’s largest manufacturer of small gasoline engines. It has sold more than 125 million of the engines. At one point, it employed about 11,000 people in the Milwaukee area.

As part of the bankruptcy filing, KPS Capital Partners LP, a private equity firm, through a newly formed affiliate has entered into an asset purchase agreement with Briggs to buy all of the company’s assets for approximately $550 million.

The so-called stalking horse bid sets a minimum price for the company’s assets.

Briggs expects to sell its assets under the supervision of the bankruptcy courts, according to a news release from KPS Capital.

The first has agreed to provide $265 million to finance Briggs’ operations during the bankruptcy proceeding.

KPS also said that it has entered into an agreement in principle with the United Steelworkers of America for a new collective bargaining agreement for Briggs hourly employees represented by the union at the company’s plant in Wauwatosa. The agreement would become effective upon completion of the acquisition and reorganization.

“KPS is committed to the expeditious acquisition of Briggs & Stratton to provide certainty of outcome and confidence in the new company’s future for all of its stakeholders, including customers, employees and suppliers,” Michael Psaros, co-founder and co-managing partner of KPS, said in statement.

“The Company and its stakeholders will benefit from KPS’ demonstrated commitment to manufacturing excellence, continuous improvement, global network, access to capital and significant financial resources,” the statement said. “The new Briggs & Stratton will be conservatively capitalized and not encumbered by its predecessor’s significant liabilities.

“We thank the United Steelworkers of America for its support of our acquisition of the company,” Psaros said in the statement.

Briggs & Stratton joins other large companies — many of them in the retail and energy sectors — that have filed for bankruptcy in recent months.

The company, based in Wauwatosa, had revenue of $1.8 billion and employed an average of 5,251 people companywide in its fiscal year…