This generator has only been used as a'Stand-by' and has had very little use. Powered by a Briggs & Stratton Vanguard engine. If used reasonably frequently - starts first pull every time. Below is the manufacturers information. Briggs & Stratton VanguardT engine. The Briggs & Stratton ProMax 6000A 4800W/6kVA petrol generator has been designed for premium performance and extended life operation. A portable generator for professional use, it is powered by a 10hp OHV VanguardT engine. The new large 38mm diameter round tube frames and, where applicable large metal fuel tanks, protect the engine and alternator. The Vanguard engine offers the best combination of durability, reliability and performance in the commercial class of air-cooled engines. It out-performs the competition for power and maintenance characteristics and is fully supported by the Briggs & Stratton service network. This model features AVR (auto voltage regulator) which is a must for powering sensitive equipment such as PCs and flat-screen TVs.