Hi, can anyone advise how the fuel lines should be connected correctly on the fuel tap?

The larger one goes to the carbs, obviously enough (no fuel filter?!).

On mine there is a small loop of narrow gauge fuel hose running between the spigot on the side of the tap assembly - the one that looks like the diaphram connection - and another small spigot on the front of the tap assembly, purpose unknown.

I also have a similar small hose coming from a carb vaccuum take off point and ending in free space.

I guess that this was originally connected to the spigot on the side of the fuel tap to control the diaphram.

So what is the other small spigot for?

I connected a tube to the side spigot, the one I think is the diaphram connection, and sucked gently... and got a mouthful!! So I imagine the diaphram is shot. Sort of explains why they rigged it this way. However, no fuel comes out of the main hose under gravity regardless of the fuel tap selection, so something seems wrong here.

Cheers.
Theo

Fuel filter is part of tap and protrudes into the tank. There are three hose connections, the large one as you have concluded is fuel outlet, the one pointing down is a vent for the diaphragm and the third is the vacuum connection from the cylinder inlet port. There must be a vacuum signal to get fuel flow no matter what the tap setting, unless the tap has the HRC mod, which removes the vacuum signal requirement. Suspecting a dud diaphragm is probably correct, not sure if replacement diaphragms are still available, probably easier to replace tap with a working used one or convert tap toe HRC type.

Cheers, I found the info on the HRC mod, I think that is the way to go.
I assume that it was leaking out of one or both of the small ports so they just connected them together!! It must have worked somehow because it was being ridden like that (but leaking dangerously).
Cheers.
Theo

http://www.nrp-carbs.co.uk/shop/index.p ... ct_id=2277

NRP sell a diaphram rebuild kit for the NC24.