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MG TD TF 1500 - Carburetor balance

My carbs were running quite rich as judged by the black soot on each plug. I check the points, plug gap, etc. and then removed the air filters (not easy on a TF)and balanced the idle. I installed the color tune on the #2 plug and it showed a very yellow flame. I was able to get the flame to show a nice blue color and then I moved the color tune to the #4 plug. I could not get away from the yellow flame no matter what I did with the mixture setting. Just off the bottom position with the mixture nut to full closed I still had a yellow flame. The car runs just fine but I worry that I am not getting full power.
Is there something I should be doing to the aft carb? Should I change the needle to a leaner needle? Or, should I re-install the air filters and not worry about it?
LD Kanaster

Hi LD,

First step with your query, as with many others, is check out the Archives. There are many reasons for a too rich mixture, and most of the answers can be found there. Unless the needles are very worn, or not seated properly, or of different markings, my advice would be look elsewhere first of all !

Good luck,

J C Mitchell


A quick check to eliminate the simplest cause is to determine that the jet is returning to the full up position when the choke is off. It should be hard against the mixture adjusting nut. Missing return spring, misadjusted linkage, are two reasons the jet may not return to the full up position. Checking float level may also be needed.


Jim Haskins

1953 TD
J. M. Haskins

Copy/paste the following into your Web browser (doesn't seem to "click") for a real education, courtesy of Dave Braun-
Jim Northrup

Look down the list for "Rear plugs sooting up....fix?" I have had the same problem. The members have given some great advice.
C.R. Tyrell

This thread was discussed between 20/06/2012 and 21/06/2012

MG TD TF 1500 index

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