Good afternoon from a very wet N Ireland, I have just fitted a correct re-conditioned 26VA Zenith Carb as my old one was from an Austin 10. The car starts on the choke and runs with revs going up and down, however at half choke it cuts out,there is some spitting when trying to keep it going. when I got the engine warmed up on the choke, I turned it off, pushed the choke full in and tried to start the engine, it started first time and only ran for a few seconds before cutting out and continued to do this every time I tried to start it.

Any help appreciated as always, Stephen.

Hi Stephen,

One of our club members had exactly the same problem. The first thing I did was check that the manifold face of the carb was flat. As the two fixing studs are at the outer edges of the carb flange it become distorted over the years as there is less pressure in the middle. Check your flange to make sure it is flat. His was shaped like a banana !

If it is not then air is sucked into the manifold causing a very weak mixture. Pull the choke out and this richens the mixture letting the engine run.

Just a thought, something which is often overlooked.

I am intrigued to see that you were running the car on a 10 hp carb. Having said that the recondtioned one for an A7 usually has 7 stamped on the top of the flange.Has It? If not check that the choke size is 17. this is marked on the outside of the orifice , if you remove the choke flap assy. (flame trap) you can see it clearly . The jets should be 50 and 57.Were they new or did they come from the old carb? incidently it is not uncommon that the jets could block on a newly installed unit . suggest a check. so with a 17mm choke and the correct jets it should work.hop ethis gives you some ideas. Mac

Hi the re-conditioned one has 7 stamped on the flange and the correct jets, I hope to get at it on Thursday and seal the flange gasket with a gasket sealant and see if this sorts it out(after I have checked that the flange face is flat, as suggested). Will let you know how it goes,unfortunitly the day job gets in the way at times.

Stephen.

Problem solved, flatened flange and sealed with sealant, still only on half choke and fluctuating revs. Took the old bowl off and fitted to re-con carb, engine ran correctly, changed over jets from new bowl to old and refitted, everything running correctly, must have been a fault in the re-con bowl. I hope to get out for a run on Sat. Once again thanks for all your help!!!

Stephen.