A handheld engine-driven working machine comprises an internal combustion engine and an ignition control device; wherein the ignition control device can switch its control between a normal mode and a operation mode, wherein during the operation mode, the ignition timing within the high speed range is maintained at a second BTDC angle, and the ignition timing within the medium speed range is advanced more than a third BTDC angle between a first BTDC angle and the second BTDC angle, and wherein at any rotational speed within the medium speed range, the ignition timing during the operation mode is advanced more than the ignition timing during the normal mode.

A handheld engine-driven working machine comprises an internal combustion engine and an ignition control device; wherein the ignition control device can switch its control between a normal mode and a operation mode, wherein during the operation mode, the ignition timing within the high speed range is maintained at a second BTDC angle, and the ignition timing within the medium speed range is advanced more than a third BTDC angle between a first BTDC angle and the second BTDC angle, and wherein at any rotational speed within the medium speed range, the ignition timing during the operation mode is advanced more than the ignition timing during the normal mode.

A handheld work apparatus has a combustion engine and an ignition device for controlling a spark plug. The ignition device includes an electronic control device having a short circuit button for switching off the combustion engine. A temperature sensor is for capturing an operating temperature. The short circuit button and the temperature sensor are connected to a common signal input of the control device via a common signal line. The temperature sensor is an ohmic resistance variable on the basis of the temperature. A measurement voltage dropped across the resistance of the temperature sensor is supplied, as an analog temperature signal, to a common analog signal input of the control device. The measurement voltage at the temperature sensor collapses in the button position of the short circuit button, as a result of which the analog temperature signal applied to the analog signal input of the control device is extinguished.

A handheld work apparatus has a combustion engine and an ignition device for controlling a spark plug. The ignition device includes an electronic control device having a short circuit button for switching off the combustion engine. A temperature sensor is for capturing an operating temperature. The short circuit button and the temperature sensor are connected to a common signal input of the control device via a common signal line. The temperature sensor is an ohmic resistance variable on the basis of the temperature. A measurement voltage dropped across the resistance of the temperature sensor is supplied, as an analog temperature signal, to a common analog signal input of the control device. The measurement voltage at the temperature sensor collapses in the button position of the short circuit button, as a result of which the analog temperature signal applied to the analog signal input of the control device is extinguished.

A lubricating oil composition and method of operating a boosted internal combustion engine with reduced low-speed pre-ignition events and corrosion resistance. The oil composition includes a base oil, one or more overbased calcium sulfonate detergents, one or more overbased calcium phenate detergents, and one or more overbased magnesium-containing detergents. A ratio of ppm of calcium to TBN of the oil composition is less than 170; a ratio of ppm of magnesium to total soap content in wt. % is greater than 700; and there are limited amounts of boron and molybdenum, and all weight percentages and ppm values being based on the total weight of the oil composition. The compositions give low LSPI ratios and pass the Ball Rust test.

A lubricating oil composition and method of operating a boosted internal combustion engine with reduced low-speed pre-ignition events and corrosion resistance. The oil composition includes a base oil, one or more overbased calcium sulfonate detergents, one or more overbased calcium phenate detergents, and one or more overbased magnesium-containing detergents. A ratio of ppm of calcium to TBN of the oil composition is less than 170; a ratio of ppm of magnesium to total soap content in wt. % is greater than 700; and there are limited amounts of boron and molybdenum, and all weight percentages and ppm values being based on the total weight of the oil composition. The compositions give low LSPI ratios and pass the Ball Rust test.

A magneto timing control system is described. The magneto timing control system can include an element configured to adjust tension of one of a first section of a belt and a section of the belt, wherein the belt is in communication with at least one magneto. The tension of the first section of the belt and the second section of the belt control a timing advance and a timing retard of the at least one magneto.

A magneto timing control system is described. The magneto timing control system can include an element configured to adjust tension of one of a first section of a belt and a section of the belt, wherein the belt is in communication with at least one magneto. The tension of the first section of the belt and the second section of the belt control a timing advance and a timing retard of the at least one magneto.

A lubricating oil composition and method of operating a boosted internal combustion engine. The lubricating oil composition includes greater than 50 wt. % of a base oil, one or more overbased calcium sulfonate detergent(s) and one or more overbased calcium phenate detergent(s). The calcium, boron, nitrogen, and amount of soap are maintained within certain ratios, and the total base number contribution from all detergents to the lubricating oil composition is less than 4.2 mg KOH/g of the lubricating oil composition, as measured by the method of ASTM D-2896. The lubricating oil composition and method may be effective to reduce low-speed pre-ignition events in a boosted internal combustion engine lubricated with the lubricating oil composition relative to capable lubricating oil compositions.

A lubricating oil composition and method of operating a boosted internal combustion engine. The lubricating oil composition includes greater than 50 wt. % of a base oil, one or more overbased calcium sulfonate detergent(s) and one or more overbased calcium phenate detergent(s). The calcium, boron, nitrogen, and amount of soap are maintained within certain ratios, and the total base number contribution from all detergents to the lubricating oil composition is less than 4.2 mg KOH/g of the lubricating oil composition, as measured by the method of ASTM D-2896. The lubricating oil composition and method may be effective to reduce low-speed pre-ignition events in a boosted internal combustion engine lubricated with the lubricating oil composition relative to capable lubricating oil compositions.