Loosened fuel line from fuel pump to carburetter, turned engine over and no fuel leaking out at the pump – indicates no fuel would get into the carb. Noticed one of the corners of the metal fuel line from pump to carb very slightly flattened, but nothing to cause any real restriction. Undid line from tank to pump – bone dry. Attached hose to the fuel line from tank and sucked. Nothing but vapours. Blew threw it and loud echo noises inside fuel tank. Whilst everything is undone, took fuel pump out and cleaned. Tested and proven that pump is functional, when lever is manually moved it does suck fuel (from a bowl via a hose) and pump it out – proves the diaphragm is not worn out. Tested the fuel pump cam in engine and that works – pushes a screwdriver blade down as engine turns over. Bolted pump back on and tightened all pipes. No difference to start up.
Possible problem fuel line:
Fuel pump installed on engine: