Joined: Sep 2017 Posts: 175 Threads: 66
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Hi guys,
I know this has been covered many times before but I'm stuck, the carb drips after switching off and even sometimes comes out of the 2 pin holes on top of the float chamber when running or just switched off.
I have replaced the needle valve and tried every combination of washer supplied with the needle.
Replaced the emulsion gasket (is sealant needed)
Tried a different float, and 2 gaskets behind the fuel pump(which is new ) It still drips
Any other suggestions gratefully received
(would it matter if the replacement needle valve from Burlens is longer in length ?)
Joined: Aug 2017 Posts: 888 Threads: 48
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Location: North Wiltshire
Car type: 1927 Chummy, 1938 Big Seven 1/2 a Trials Chummy
Friend of mine had a similar problem. He was using an AC "U" type pump. Once he replaced it with a "T" type, the problem went away.
Maybe the "U" type developed more pressure??
Or maybe the "T" type was less efficient??
Joined: Aug 2017 Posts: 1,355 Threads: 244
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Location: North Herts
I had this with a 26VA last week. Cured by use of a thicker washer under the needle valve. Probs about 1.5mm thick.
Joined: Sep 2017 Posts: 175 Threads: 66
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Nick, I've tried all 3 washers and combination of but to no avail
Joined: Aug 2017 Posts: 1,355 Threads: 244
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Location: North Herts
Have you tried taking off the float bowl, holding up the needle valve, and using the priming lever on the fuel pump (assuming it has one)? This to see if the needle is properly cutting off the fuel flow under pressure.
Joined: Aug 2018 Posts: 190 Threads: 5
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Location: Dorset seaside
I had this with one of mine , I couldn't stop it , in the end I sent it to Steve Hodgson to recon it and he found the emulsion block on the side of the bowel was porous.
Joined: Sep 2017 Posts: 175 Threads: 66
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Just tried that Nick, holds the fuel back well until I let it go !
Nigel do you have his contact details might be worth a go, what does he charge, did he refurbish the whole carb or just the emulsion block ?
Joined: Mar 2015 Posts: 5,469 Threads: 231
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Location: Scotchland
If the spring in the pump is too strong/heavy it will cause this problem.
Joined: Sep 2017 Posts: 175 Threads: 66
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It's a new pump R from seven workshop, can the spring be weakened ?, somebody on Facebook said he'd used a 6mm spacer between pump and crankcase
Joined: Aug 2018 Posts: 190 Threads: 5
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Location: Dorset seaside
Steve Hodgson trades as SMH Services and is well thought of in A7 circles, I sent the whole carb to Steve and he reconditioned the whole thing including rebushing the carb spindle and fitted a new emulsion block, I think the cost was about £100 and turned around in less than a week. Google SMH Services.
