A bit of a long shot. I just acquired a small gas boat barbeque (sea chef). Unfortunately the venturi pipe is missing. I was wondering if anyone has a picture of what the pipe might look like. Might be similar to a Magma.
It seems to be a Force 10 product, although it appears they don't sell that model anymore; perhaps ask them if spares are available or if not if they could supply an exploded diagram which could help in making a substitute? This person has found a workaround.