Joined: Jul 2019 Posts: 187 Threads: 42
Reputation:
5
Location: North Wales UK
Car type: Austin 7 RN 1931
A little bit of help please.
My RN refuses to start even when warm unless I 'tickle' the carb. It starts straight away once I've done that.
It runs like a little sewing machine once started and doesn't miss a beat. The jets are clear and I have a good quality filter on the fuel line.
I've fiddled with the various settings on the carb to no avail including playing with the float height.
Am I missing something so basic that I can't see the wood for the trees?
Buy an Austin 7 they said, It's easy to work on they said !
Joined: Mar 2015 Posts: 5,461 Threads: 231
Reputation:
67
Location: Scotchland
27-02-2022, 11:18 AM
(This post was last modified: 27-02-2022, 09:48 PM by Ruairidh Dunford.)
My father’s Chummy almost always requires flooding and full choke to start - it has been so since 1970 I believe.
Our other Zenith carb cars just require this when cold.
Following with interest…
Joined: Aug 2017 Posts: 3,019 Threads: 169
Reputation:
37
Location: Sherwood Forest
Car type: 1938 Talbot Ten Airline
My RM is similar: there doesn't appear to be any signs of leakage from the carb, but if I turn the petrol tap off then the carb will need flooding on restarting. If I leave the petrol turned on, then usually it will start without assistance. I seem to recall my coupe also needed flooding to start - hot or cold. I just live with it as a fact of life!
Joined: Aug 2017 Posts: 886 Threads: 48
Reputation:
4
Location: North Wiltshire
Car type: 1927 Chummy, 1938 Big Seven 1/2 a Trials Chummy
Does this refer to the original 22FZB carburettor?
If so, I've found that careful adjustment of the "slow running jet", which is actually a small auxiliary carburettor is beneficial. This auxiliary carb is only used when running slowly and when starting the engine - there's quite a good description of it in the Nicholson book.
Adjustment is a balance between easy starting and low fuel consumption but all this assumes that the slow running tube is not split or damaged from being mishandled in years gone by.....
Joined: Aug 2017 Posts: 3,019 Threads: 169
Reputation:
37
Location: Sherwood Forest
Car type: 1938 Talbot Ten Airline
Certainly an FZB on my car, which has been rebuilt and set-up by Dave Mann and now gives better than 50mpg under all conditions so I am not adjusting the slow-running tube!
Joined: Mar 2018 Posts: 697 Threads: 33
Reputation:
3
Location: Lot region FRANCE
My RN - always start on choke, hot or cold, as soon as she starts, put the choke back in. When cold, start on full choke, pop it back in as soon as it fires and after a few seconds, the revs die down, catch the engine by pulling choke back out, revs go up and pop the choke back in. When very cold (-4C or more), you may have to coax the engine into life with pulling choke out/in 3 or 4 times.
If you leave the choke out all the time, the engine stalls. (On my RN).
