The problem can be caused by any of the following issues:
1: gradient being steeper than the recommended tilt advised for the engine.
2: poor fuel suction from carb to tank. this can be solved by cleaning the filters and adjusting the carb whilst the engine is in 2 states. idle and running.
3: depending on the engine and where the fuel tank is situated to the machine, fuel will not pump. most engines are only designed to handle a 20 / 30 degree max incline / slope due to the fact that the engine has to keep the piston constantly lubricated. some engines cannot fully coat the piston in oil (full pump) because of their design. more advanced engines including honda and Briggs & Stratton have driven oil pump units fitted so that they can handle inclines.
Steep inclines are best tackled using a 2 stroke hover mower such as a husqvarna or allen, etc or flymo contractor because they are able to handle inclines due to the fact that both oil and fuel are blended and not separate.
Edward Redfern, December 2012
