Exhibit 99.1

POWER SOLUTIONS INTERNATIONAL, INC. REPORTS THIRD QUARTER 2011 RESULTS

Wood Dale, IL – Nov 14, 2011 - Power Solutions International, Inc. (OTC-BB: PSIX.OB) today announced its financial results for the third quarter and nine months ended September 30, 2011.

Third Quarter 2011 Financial Highlights:

Net sales for the third quarter of 2011 were $42.8 million, an increase of $15.6 million or 57% from the third quarter of 2010 and a 21% increase from the second quarter of 2011. The Company reported net income of $1.9 million or $0.19 per diluted share in the third quarter of 2011 compared to $.05 per diluted share in last year’s third quarter. Growth during the quarter was driven by strong unit volumes to Asia and in the domestic material handling market.

“We are pleased with the strong growth in our business,” said Gary Winemaster, PSI’s Chief Executive Officer. “Our business continues to improve as a result of the improving economic conditions for our customers. More significant, however, has been the major impact of our new product and new market initiatives. As an example, we started shipping to Asian-based customers in 2010, and that part of our business is growing rapidly as our products’ design superiority and value proposition become increasingly embraced.”

Gross profit for the third quarter of 2011 was $6.6 million. The gross profit margin was 15.3%. This compares to 15.1% in third quarter of 2010, but was down from the 18.4% gross margin in the second quarter of 2011. The Company reported that its sales mix contributed to the decline in gross margin on a sequential basis and expects to see improvement in the near-term.

Operating profit of $2.3 million was more than double from the third quarter 2010 but down somewhat from the second quarter 2011 operating profit of $2.6 million. The sequential decline in operating profit was due to the lower gross margin, offset in part by operating expense leverage.

Other income and expense, which includes interest expense, was $396,000 in the third quarter. This includes non-cash income of $585,000, resulting from a decrease in the estimated fair value of the liability associated with the warrants issued in the Company’s April 2011 private placement.

Net income for the third quarter of 2011 was $1.9 million. Of this amount, $1.1 million was allocable to the average outstanding shares of the Company’s Series A Convertible Preferred Stock during the quarter. The balance of $786,000 of earnings was allocable to common shareholders, of which there were 4.1 million average shares outstanding during the quarter. This represents diluted EPS of $0.19, which compares to diluted EPS of $0.05 in the third quarter of 2010. The Company said its capital structure was simplified during the quarter, with all of the preferred shares converted into common shares as of August 26, 2011.

Sales for the nine months ended September 30, 2011 were $109.5 million, an increase of $38.9 million or 55% from $70.6 million during the same period last year. Net income for the nine month period was $3.5 million or $0.38 per common share, compared to $0.8 million, or $0.10 per common share, for the same period in 2010.

“The whole team at PSI is excited by the progress we have made in our first full quarter as a publicly traded company,” said Gary Winemaster, Chief Executive Officer. “We believe we have the right products and leading technologies, and along with our talented group of employees, are well positioned for future growth. The abundant supply of natural gas and continuing movement toward clean fuels will drive strong growth for alternative-fueled engines, attracting more applications over time. PSI intends to be the leader in this expanding market.”

Third Quarter Conference Call and Presentation

The Company will discuss its financial results and future outlook in a conference call today at 4:30 p.m. EST, hosted by Gary Winemaster, Chief Executive Officer, and Tom Somodi, Chief Financial Officer. Investors in the U.S. interested in participating in the live call should dial +1 (888) 378-4361 and enter passcode: 6483352. Those calling from outside the U.S. should dial +1 (719) 325-2249 and use the same passcode: 6483352. A telephone replay will be available approximately two hours after the call concludes through November 21, 2011 by dialing from the U.S. +1 (877) 870-5176, or from international locations +1 (858) 384-5517, and entering passcode: 6483352. There will also be a simultaneous live webcast that will be available at http://www.powersint.com. The webcast will be archived on that website.

About Power Solutions International, Inc.

Power Solutions International, Inc. (OTC-BB: PSIX.OB) is one of the leaders in the design, engineering and manufacture of emissions-certified alternative-fuel and conventional power systems. PSI can provide integrated turnkey solutions to leading global original equipment manufacturers in the industrial, off-road and on-road markets. The Company’s unique in-house design, prototyping, engineering and testing capacities enable the customized production of clean, high-performance engines that run on a wide variety of fuels, including natural gas, propane, biogas, diesel and gasoline. PSI develops and delivers complete .97 to 22 liter power systems that meet both its customers’ specific power needs and applicable environmental standards. The Company also provides aftermarket products and support. PSI power systems are used worldwide in power generators, forklifts, aerial lifts, and industrial sweepers, as well as in equipment for oil and gas production, aircraft ground support, agriculture, and construction.

Cautionary Note Regarding Forward-Looking Statements

This press release contains forward-looking statements, including statements regarding the current expectations of Power Solutions International, Inc. (the “Company”) about its prospects and opportunities. The Company has tried to identify these forward looking statements by using words such as “expect,” “anticipate,” “estimate,” “plan,” “will,” “would,” “should,” “forecast,” “believe,” “guidance,” “projection” or similar expressions, but these words are not the exclusive means for identifying such statements. The Company cautions that a number of risks, uncertainties and other important factors could cause the Company’s actual results to differ materially from those expressed in, or implied by, the forward-looking statements, including, without limitation, the current challenging economic conditions, the development of the market for alternative fuel systems, changes in environmental and regulatory policies, significant competition and the Company’s dependence on key suppliers. For a detailed discussion of factors that could affect the Company’s future operating results, please see the Company’s SEC filings, including the disclosures under “Risk Factors” and “Cautionary Note Regarding Forward-Looking Statements” in those filings. Except as expressly required by the federal securities laws, the Company undertakes no obligation to update or revise any forward-looking statements, whether as a result of new information, changed circumstances or future events or for any other reason.

Contact:

Power Solutions International, Inc.

Dan Gorey

Senior Vice President of Finance

+1 (630) 451-2290

dgorey@powergreatlakes.com

or

ICR, LLC

Scott Arnold

Senior Vice President

Investor Relations Consultant

(310) 954-1107

scott.arnold@icrinc.com

Power Solutions International, Inc.

Condensed Consolidated Balance Sheets

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Power Solutions International, Inc.

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Power Solutions International, Inc.

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