On Thu, 21 Dec 1995 KeithB227@aol.com wrote:
> Using the colortune I find that I have an excessively rich (yellow combustion
> color) mixture in all cylinders which hardly changes at all with jet
> adjustment. I can even have the jets cranked all the way up flush with the
> base and the colortune still shows very rich combustion. I've checked and
> doublechecked the usual things: needle shoulders are flush with the piston
> surface, jets are centered, pistions don't stick, float chambers are not
> flooding, float needles are new, and I'm pretty sure I have the float levels
> set correctly at about 1/8th inch.
> Other things like timing, point gap/dwell, valve lash, are adjusted and seem
> to be fine.
> How can I have a funky idle with air leaks and an uncontrolably rich mixture
> at the same time!?! The DPO seems to have been satisfied with a very erratic
> 1400-1800RPM idle, since it runs great as long as you're accelerating. I'm
> beggining to wish I was satisfied with it also, as it's ruining my holiday
> spirit! Any help would be greatly appreciated.
Been there. The colourtune doesn't actually tell you the mixture. It
just shows you one view of the flame. I had old, high resistance plug
wires and the colourtune showed "rich" even when the carbs were so leaned
out you couldn't drive it. Once I got the new wires on the mixture
adjusted by ear (lift the piston) easily. Colortune is interesting but I
don't need it and wish I'd saved the money. I will be spending some
soon. Baby wants an engine rebuild for Christmas.
Anyway, back to your problem. Bad coil, cap, rotor, wires, or plugs
(well, the colourtune _is_ your plug in this case) will give you a poorer
"yellow" burn. Make sure you're getting good spark.
Kevin Sullivan -- 1960 MGA
Nichols Research Corp.
Shalimar FL USA