View Full Version : Spitfire Sooty Spitty 79 W/Weber DGV

09-22-2004, 09:24 AM
I hae the 32mm/36mm on my 79 Spit. Great performance. However, when starting I get a blast of black soot and smoke from the exhaust. The car burns minimal oil and does not smoke when driven at speed.
Using a new stock mechanical fuel pump without a pressure regulator, carb has electric choke.
Any input would be helpful.

R&M /ubbthreads/images/graemlins/confused.gif
Is there a jet change that can be made?

Simon TR4a
09-22-2004, 11:13 AM
I don't know a lot about the downdraft Webers, my Spit has a 40 DCOE sidedraft, but this sounds like a rich idle jet or some problem with the choke, since it occurs only at start-up. I believe the correct idle jet should be a 55 (.055 millimetre), but you should research this with Pierce Manifolds, Redline or APT who supply Weber conversion kits.
Remove the jet stack and write down the numbers on the idle jet, primary jet, emulsion tube and air correction jets and compare with recommendations from the supplier.
Since you have indicated the car runs well I think only the idle jet is in question, or the choke, of course.
Good luck! Simon.

09-22-2004, 07:14 PM
Thanks for the input. Choke operates fine. I will try your other suggestions. By the way is is colder & we get more snow in Buffalo than you do in Ontario.

Thanks again for the help.

R&M /ubbthreads/images/graemlins/canpatriot.GIF

Webb Sledge
09-23-2004, 06:45 PM
My TR6 has twin Strombergs and it does this as well. If I'm not mistaken, the soot is carbon, which would normally be trapped in the carbon canister, except mine probably needs to be changed or cleaned. Check that before you go messing with the carburetors.

09-23-2004, 07:18 PM
Webb, the carbon canister has absoultely nothing to do with soot. It is for the vapor recovery portion of the emissions control system.
Soot or black smoke from the tailpipe is indicative of an over rich mixture, which could be the result of several possibilities. Sticky choke(s), low compression, fouled plug(s), improper jet adjustment or incorrect jet, etc.