Joined: Aug 2017 Posts: 849 Threads: 123
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The AD Chummy has an updraft T24 Carburettor. I have stripped it & cleaned the muck out, checked the jets are the recommended ones & put it back on with a new gasket. The car started well, but will only run with the choke fully out!
It will rev a bit and even tick over like this, but this is not a good long term plan!
No clouds of petrol-ly smoke, sounds quite healthy, but something is clearly wrong somewhere.
Took the carb off again to see if the slow running jet was blocked, but no: clear.
Put it back together, same result.
Mixture screw 1 1/2 turns out from fully in.
What next to try?
Previous owner said it ran earlier this year, but it may have been like this!
David
Joined: Aug 2017 Posts: 3,019 Threads: 169
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Location: Sherwood Forest
Car type: 1938 Talbot Ten Airline
Sounds like a blockage in the main jet.
Joined: Dec 2017 Posts: 1,160 Threads: 68
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Location: Nottinghamshire. Robin Hood County
Car type: Austin Ruby Mk1 1935
08-11-2018, 08:40 PM
(This post was last modified: 08-11-2018, 09:01 PM by John Mason.)
Could you possibly have air leaks somewhere. It sounds to me like extra air maybe getting in resulting in weak mixture.
John Mason
Would you believe it "Her who must be obeyed" refers to my Ruby as the toy.
Joined: Aug 2017 Posts: 3,418 Threads: 107
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Location: Darkest Bedfordshire
Yes, worth checking manifolds are sealing properly at joint faces.
Joined: Aug 2017 Posts: 2,748 Threads: 31
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Location: Auckland, NZ
Seems unlikely in this case but very stale petrol will often run only with lotsa choke
Joined: Aug 2017 Posts: 60 Threads: 4
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Location: Northland New Zealand
Dave, check that the fuel tap isn’t blocked. My Chummy had the same. problem when I got it after it had been laid up for a year or two.
Bryan
Joined: Aug 2017 Posts: 849 Threads: 123
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Thanks all
Plenty to look at!
D
Joined: Mar 2015 Posts: 5,466 Threads: 231
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Location: Scotchland
I seem to recall that there is a jet underneath or at the front somewhere on these carbs as well and inside the body - could be wrong but may well be worth checking.
Joined: Aug 2017 Posts: 143 Threads: 30
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Location: New Forest
Car type: 27 Chummy
Hello David
Do you have a fixed main jet or the adjustable one.
Symptoms sound similar to adjustable jet too lean.
Adrian.
Joined: Aug 2017 Posts: 989 Threads: 6
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Location: Scottish Borders
I agree with Mike, blocked main jet.
Had exactly that problem yesterday with the FZ22 carburetor on my 1929 Saloon. Started easily and ran OK on full choke. No power and wouldn't rev. Stalled as soon as choke closed even slightly. Cleaned jets - all OK.
Jim
