Choke, air strangler
- by Ian Moorcraft
- Download this article here
I have always had a key ring to pull out the choke and a kink in the wire to keep it there. I have often wondered what the original arrangement could have been.
A question from someone on the AustinSevenFriends forum “How do you keep the choke out ?” was answered by regular contributor Tony Press in Australia. His answer was that the ring was a 1” outside diameter brass ring of 1/8” cross section. There is a brass ‘top hat’ ferrule 1” long that keeps the choke out when dropped into the slot in the bracket under the dash.
As you can see from the photo I now have this arrangement on my ’28 Chummy, it is shown with the choke pulled out, and is lifted so the brass ferrule can slide through the hole at the top of the slot.
I made the ring from 1/8” brass rod, annealed and wrapped around a piece of ¾” tube the join being soldered. Previously ordered cast brass rings on Ebay went straight into the bin, as they were not round or a consistent cross-section, so making your own is the best option for a neat job. I ordered 300mm of 1/8” brass round bar from www.engineering-suppliers.co.uk at a cost of £2.59 including free postage !
I could see that drilling a 1/16” hole for the choke wire to pass through an inch of brass with my hand drill was going to be difficult if not impossible to make the ferrule, and I think a challenge even if I had a lathe. So in the time honoured tradition of true A7 enthusiasts (rather than cheque book Charlie’s) scoured the workshop for something to make it from.
Have any of you already spotted that it is a cut down second-hand crankcase oil jet? I also added a small brass washer against the shoulder to give a little extra bearing surface on the bracket.
Checking through my parts lists I see that this arrangement with the ferrule BE77 first appears about halfway through 1925 when the new ‘keyhole slotted’ dashboard bracket part number BE78 supersedes BE70 which just had a round hole, this one appears not to have any obvious means of keeping the choke out.
The bracket BE78 ring BE69 and ferrule BE77 was still listed for 1931 RL/RM and maybe RNs even though now positioned above the steering column.
I recall reading in one of the ‘Austin Service Journals’ dealers were advised to remove the small screw for locking the choke out on later knob pull chokes to discourage owners from running with the choke out causing premature wear of the bores. Apparently causing too many claims under warranty !