Abstract: The present invention provides for an internal combuston engine having housing parts such as a cylinder, cylinder head and crankcase formed of a light metal. A plurality of tightening screws are provided for securing the above-mentioned parts so as to form an engine block, the screws having threaded ends which are received in the heads of steel tie rods which are integral with the crankcase and which extend substantially parallel to the cylinder axis. When the engine is in use, the tightening of the light metal housing parts by way of the steel tie rods, prevents undesired deformation of the crankcase.

Abstract: A decompression apparatus for an internal combustion engine includes an adjustable eccentric decompression cam which pivotally supports a rocker arm which controls a valve. A switching member supported on and operable by the rocker arm during decompression causes the cam to move in progressive steps from a decompression position to a non-decompression position. The switching member is moved to an operative position at the start of decompression by one of two projections provided on the cam, and as the cam moves into its non-decompression position the other of the projections thereon moves the switching member to a non-operative position. A locking mechanism releasably holds the switching member in its non-operative position.