| abstract |
The subject invention refers to a drive unit (1) for a handheld working tool, such as a chain saw, trimmer or hedge trimmer, said drive unit essentially comprises a housing part (2) with a fuel tank (3) and an engine unit (4) with a fuel supply unit (5), such as a carburetor (5), a muffler (6) and a crankcase scavenged combustion engine (7), with cylinder (8), piston (15) and crankshaft with a centre (17). In accordance with the invention the engine (7) has at least one inlet port (9) located in the cylinder wall (10) of the engine and/or an adjacent part of the engine crankcase (11), and the engine's inlet duct (13) from the inlet port (9) up to the fuel supply unit (5) has a length longer than 1.8 times the engine cylinder stroke (18), preferably longer than 2.0 times the cylinder stroke (18). |