Forums General Counties Cars Discussion A40 Somerset fuel drain back. Reply To: A40 Somerset fuel drain back.


Hi there Robin,

The last time I stripped a similar carb was back in 1965, which was on a ’49 Hampshire, so my memory is a little faded.   Since 1967 though, I have had A90 Atlantics that have twin SU’s.  However, I do  have  ’54 Hereford engine on a test rig that I use for checking A70/90 gearboxes after reassembling them for testing. This engine only has around 35,000 miles on it, and the carby is original, which I think would be the same, and possibly pretty much like that on the Sommerset.  This engine can sit for many months in between starts, and when needed, apply the choke, and in a few seconds it is away.

From memory, in the base of Hampshire carby there is a small ball valve, and if the carb has been stripped for cleaning, and it is also supposed to have the ball valve, is it in place.  May I suggest to get an appropriate container ready with a block in its center, then to run your engine for several minutes, then switch off, and immediately remove the carb with the bowl full, sitting it on the block in the container.  Such should allow you to see if there is a leaking problem.

I have a fellow Atlantic owner, who in his younger days owned around 15~20 A40’s, though not sure if it included any Somersets. I have phoned him for some thoughts on your problem, but he has not thus far responded. I will let you know if he can offer anything that might be a cause of your problem.  I do think though that the check I have described should at least give some indication of a leak.

Hope it assists in some small way.

Happy Austineering,

Peter Hackney.