Hi Veggie, please see the text below cut and pasted from the listeroid 6/1 installation manual:
EXHAUST SYSTEM: A standard engine is fitted with an exhaust silencer. If the exhaust piping be extended to
the out side of the building up to a length of 3 meters, the exhaust silencer can be fitted on the end of iron
pipe screw 1 1/2” BSP.
If exhaust system is longer, following pipe size is recommended.
Pipe line: Up to 3 meter — 38.0mm (1 ‘, 4”) Bore
3 to 6 meter — 50.8 mm (2”) bore
6 to 10 meters — 63.5 mm (2½”) bore over
10 meters — 76.Omm (3”) bore
However, keep the exhaust system is as short as possible with a minimum number of bends and must be erected in
easily detachable sections to facilitate cleaning during overhaul. Never embed in concrete. A faulty system
can seriously reduce the power of the engine.
Bob