Abstract: An apparatus or system includes a component that generates or transfers noise having a frequency within a noise frequency range. The component may include a boundary. The apparatus or system may be an engine in some examples. The engine may additionally include a micro-perforated sheet positioned a distance from the boundary. The micro-perforated sheet may include a plurality of micro-perforated holes, and may be configured to absorb sound within an absorption frequency range based on parameters of the micro-perforated sheet. The parameters may include the distance from the boundary and dimensions of the micro-perforated holes, and may be set such that the absorption frequency range overlaps the noise frequency range.

Abstract: An apparatus or system includes a component that generates or transfers noise having a frequency within a noise frequency range. The component may include a boundary. The apparatus or system may be an engine in some examples. The engine may additionally include a micro-perforated sheet positioned a distance from the boundary. The micro-perforated sheet may include a plurality of micro-perforated holes, and may be configured to absorb sound within an absorption frequency range based on parameters of the micro-perforated sheet. The parameters may include the distance from the boundary and dimensions of the micro-perforated holes, and may be set such that the absorption frequency range overlaps the noise frequency range.

Abstract: An apparatus or system includes a component that generates or transfers noise having a frequency within a noise frequency range. The component may include a boundary. The apparatus or system may be an engine in some examples. The engine may additionally include a micro-perforated sheet positioned a distance from the boundary. The micro-perforated sheet may include a plurality of micro-perforated holes, and may be configured to absorb sound within an absorption frequency range based on parameters of the micro-perforated sheet. The parameters may include the distance from the boundary and dimensions of the micro-perforated holes, and may be set such that the absorption frequency range overlaps the noise frequency range.

Abstract: An apparatus or system includes a component that generates or transfers noise having a frequency within a noise frequency range. The component may include a boundary. The apparatus or system may be an engine in some examples. The engine may additionally include a micro-perforated sheet positioned a distance from the boundary. The micro-perforated sheet may include a plurality of micro-perforated holes, and may be configured to absorb sound within an absorption frequency range based on parameters of the micro-perforated sheet. The parameters may include the distance from the boundary and dimensions of the micro-perforated holes, and may be set such that the absorption frequency range overlaps the noise frequency range.

Abstract: An air intake component and assembly, as well as an associated carburetor assembly and related method of assembly, are disclosed. In at least some embodiments, the intake component includes a surface capable of being coupled at least indirectly to a carburetor assembly, where the surface includes first and second orifices, a first channel capable of communicating engine intake air from a first location to the first orifice of the surface, and a second channel by which at least one of the first location and a second location is connected to the second orifice. The second channel is capable of communicating at least one of a primer air pressure pulse from the at least one location to the second orifice and fuel fumes from the second orifice to the at least one location. In at least some further embodiments, the intake component can be fitted with any of several interchangeable covers.

Abstract: A liquid tank such as a liquid fuel tank, as well as a method of operating such a tank and a structure for implementation in such a tank, are disclosed. In at least one embodiment, the liquid tank is a liquid fuel tank that includes a housing have an inner chamber capable of containing liquid fuel as well as an air space above an upper surface of the liquid fuel, and a floating member included within the inner chamber, where the floating member is configured to float proximate the upper surface of the liquid fuel when the liquid fuel is present within the inner chamber. The floating member includes at least one tapered surface, and the floating member covers a majority of the upper surface of the liquid fuel, whereby the liquid fuel evaporates to a lesser degree than would occur if the floating member was absent.

Abstract: An air intake component and assembly, as well as an associated carburetor assembly and related method of assembly, are disclose. In at least some embodiments, the intake component includes a surface capable of being coupled at least indirectly to a carburetor assembly, where the surface includes first and second orifices, a first channel capable of communicating engine intake air from a first location to the first orifice of the surface, and a second channel by which at least one of the first location and a second location is connected to the second orifice. The second channel is capable of communicating at least one of a primer air pressure pulse from the at least one location to the second orifice and fuel fumes from the second orifice to the at least one location. In at least some further embodiments, the intake component can be fitted with any of several interchangeable covers.

Abstract: A twin cylinder engine, includes a pair of cylinder members mounted to mounting surfaces of a crankcase, and cylinder heads mounted to the cylinder members. The cylinder members are modular components, which may be pre-assembled with components of the valve train as packaged units before the cylinder members are attached to the crankcase. Each cylinder member rotatably supports a cam gear which extends into the crankcase for driving engagement with the crankshaft. The cylinder members may be configured for either side valve-type (“L-head”), or overhead valve-type (“OHV”) engines, and the cylinder members may also be used in single cylinder engines.

Abstract: A line of small internal combustion engines, including twin cylinder engines and single cylinder engines. The engines each include a crankcase, and one or more cylinder members attached to the crankcase, the cylinder members being separate components from the crankcase. A number of different crankcases are provided for various types of single and two cylinder engines, the crankcases having common mounting structure to which the cylinder members may be attached. Thus, the manner in which the cylinder members are attached to the crankcases is the same for each of the different types of crankcases. Two different types of cylinder members are provided, one having a side valve or “L-head” valve train, and the other having an overhead cam (“OHV”) valve train. The cylinder members are therefore modular components which may be selectively used in a variety of different types of engines.

Abstract: An air cleaner for small internal combustion engines, including a removable or replaceable air cleaner element detachably mounted within an air cleaner cavity which is defined at least on part by the shroud of the engine. The air cleaner element includes engagement structure for releasable engagement with a wall of the air cleaner cavity to permit mounting of the sir cleaner element within the cavity, and removal of the air cleaner element from the cavity, without the use of tools. In addition, a cover is provided for releasably engaging the air cleaner cavity to cover the air cleaner element.

Abstract: A line of small internal combustion engines, including twin cylinder engines and single cylinder engines. The engines each include a crankcase, and one or more cylinder members attached to the crankcase, the cylinder members being separate components from the crankcase. A number of different crankcases are provided for various types of single and two cylinder engines, the crankcases having common mounting structure to which the cylinder members may be attached. Thus, the manner in which the cylinder members are attached to the crankcases is the same for each of the different types of crankcases. Two different types of cylinder members are provided, one having a side valve or “L-head” valve train, and the other having an overhead cam (“OHV”) valve train. The cylinder members are therefore modular components which may be selectively used in a variety of different types of engines.

Abstract: An air cleaner system for small internal combustion engines, including a removable or replaceable air cleaner element detachably mounted within an air cleaner cavity which is defined at least in part by the shroud of the engine. The air cleaner element includes engagement structure for releasable engagement with a wall of the air cleaner cavity to permit mounting of the air cleaner element within the cavity, and removal of the air cleaner element from the cavity, without the use of tools. In addition, a cover is provided for releasably engaging the air cleaner cavity to cover the air cleaner element.

Abstract: A twin cylinder engine, includes a pair of cylinder members mounted to mounting surfaces of a crankcase, and cylinder heads mounted to the cylinder members. The cylinder members are modular components, which may be pre-assembled with components of the valve train as packaged units before the cylinder members are attached to the crankcase. Each cylinder member rotatably supports a cam gear which extends into the crankcase for driving engagement with the crankshaft. The cylinder members may be configured for either side valve-type (“L-head”), or overhead valve-type (“OHV”) engines, and the cylinder members may also be used in single cylinder engines.

Abstract: A compression release mechanism for use in a single or multi-cylinder engine to make the engine easier to hand start. The assembly includes a compression release shaft disposed substantially within the camshaft. The compression release shaft is formed in at least two segments and can therefore be formed accurately, repeatedly and cost effectively using powder metal technology. Consequently, the weight of the flyweight member that is attached to the compression release shaft can be accurately controlled, thereby allowing the compression release mechanism to disengage at a precisely known rotational velocity of the camshaft. The compression release shaft may engage one or more valve actuation devices, which in turn force exhaust valves open during starting engine speeds. The compression release mechanism is conveniently contained within the housing by a housing wall bearing against the flyweight member and a cam bearing against an end of the compression release shaft.