Yeah as supafatto mentioned, the float bowl should be towards the front of the engine. Best to set it up this way as it avoids the fuel washing up against the float bowl wall furthest away from main jets under acceleration. This has the effect of locally lowering the fuel level in float chamber over main jets which causes a lean mixture. If you set it up with float bowl to the front (as suggested), the fuel will wash up against float chamber wall over jets causing a local increase in fuel level over main jets instead. Arguably this makes for a richer mixture, but it's better than lean!

See pm too....