G9 Carburettor (1955 model)

[TrevorB]

Just done a strip down of the 376/6 Monobloc carburettor on my G9. A previous owner had fitted a Tufnol spacer and a conventional type gasket between the carb and the manifold as well as the O-ring. Neither the spacer nor the gasket are indicated in my spare parts list. Question is.....should they be there? I assume the Tufnol spencer is there as thermal barrier between the carb & manifold but is it necessary? If so what purpose does the O-ring serve. I notice when I push the mating surfaces of the manifold and carb flange together without the O-ring, there is a small gap visible, indicating neither mating surface is perfectly flat.

[g5wqian]

i have a 56 model 30 ajs and it has no spacer or insulator and the inlet manifold is plain aluminium with no o ring .

it just uses gaskets both ends and thats all , carb is similar to yours , 1" bore and runs perfectly ok hot or cold within reason for a 61 year old machine , just the few quirks that they have like the odd backfire here and there and also the need to adjust the idle speed screw in when cold and out when hot and the odd cough when trying to pull of at the lights and you dont give it enough throttle , and when the dreaded re start confusion manifests itself and panic sets in for a few seconds so you can retard the timing and get it out of gear so you can kick it over and re start .

[leswaller]

Just done a strip down of the 376/6 Monobloc carburettor on my G9. A previous owner had fitted a Tufnol spacer and a conventional type gasket between the carb and the manifold as well as the O-ring. Neither the spacer nor the gasket are indicated in my spare parts list. Question is.....should they be there? I assume the Tufnol spencer is there as thermal barrier between the carb & manifold but is it necessary? If so what purpose does the O-ring serve. I notice when I push the mating surfaces of the manifold and carb flange together without the O-ring, there is a small gap visible, indicating neither mating surface is perfectly flat.

I have a G9 and assuming that you are using the standard manifold then all you should have is the rubber ' O' ring which is set into the carb flange. This provides the necessary seal and heat insulation, but do not over tighten the fixing nuts between the carb and the manifold or you will distort the carb body which means the slide will then stick. (don't ask me how I know!)

[TrevorB]

Many thanks for the advice. I've put the carb back on with just the O-ring between car & manifold.
Regards