Exhaust gas analyser

I have an early TA21 fitted with the original twin choke Solex carburettor. Having been given a second hand basic exhaust gas analyser I seek advise from members as to what air/fuel ratio is appropriate when setting the idle mixture for this carburettor. I feel that this question has the makings for some interesting responses.  Richard Wallach Posted by RichardWallach 10/07/2013 08:25:59

Hi Richard: My TC21 has twin SU's so am not terribly familiar with the Solex. If it is similar to most fixed jet carbs then the idle mixture is adjusted via a bleed screw which alters the amount of air at idle, but does not greatly affect the mixture at higher revs. Mixture at higher revs is altered by changing the jets. Set everything else on the engine - valve clearances, points gap (dwell), ignition timing, check for and eliminate any air leaks, and check the exhaust system has no leaks, and then, as a starting point, set it at 1.5% to 2% CO at idle. When setting the single venturi fixed jet carb on my Austin A35 (sorry - years ago!) I used to use a Gunson's colortune, or just twiddle the mixture screw to get maximum revs at idle, and then richen slightly. Good luck, Jon Posted by drdowhitt 14/07/2013 10:05:48