Lee Dutton Posted March 18, 2021 Report Share Posted March 18, 2021 Been trying to set up the carbs (SU) on my 4a, seems to be running rich (whatever I do ) checked the needles it is fitted with BAE, so I changed them to standard TW wouldn't run at all so put the BAE's back I noticed the BAE needles are at least 10mm longer than the standard TW why? Any suggestions on leaner needles to use please? Best regards Lee Quote Link to post Share on other sites
Efuentes Posted March 18, 2021 Report Share Posted March 18, 2021 Are you sure that the problem are the needles?. In my TR4A (with TR4 H6 carburetors), I had the same problem and I found out that the issues were the choke arms that pull the jets out not going back to the fully closed position due to jet sticking to the seals and a faulty choke mechanism (some previous owner changed the way the choke opens), and air leak due to worn throttle spindles. I changed the throttle spindles, jet seals and repaired the choke mechanism and was pleased to see that, for the first time since I own this car, I had to enrich the mixture by unscrewing the jet adjustment nuts. Quote Link to post Share on other sites
Lee Dutton Posted March 18, 2021 Author Report Share Posted March 18, 2021 Thanks Efuentes, will check out your suggestions and see what happens Cheers Lee Quote Link to post Share on other sites
Lebro Posted March 18, 2021 Report Share Posted March 18, 2021 (edited) The BAE needles are the sprung type, so you should not easily be able to switch to TW which is not sprung. If you did manage it, there is a strong chance that the jet would not be centralised to the needle, which would explain the difficulty. The profiles of the BAE & TW needles are very similar & one may be the sprung equivalent of the other. Bob. Edited March 18, 2021 by Lebro Quote Link to post Share on other sites
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