TR2/3/3A TR3A is running too rich

[JSpears]

My '60 TR3A is running too rich. A lot of black smoke out the back and poor gas millage. I took off the air filters, inserted a color tune in the first plug hole. I can't seem to make it NOT yellow. I tighten and loosen the brass nut under the dash pot, and I am still have a yellow spark and tons of black smoke. What am I doing wrong? I can't seem to make it lean. Am I missing something? Is there a magic chant I need to do?

 

[Roger]

Make sure that when you screw the nut upwards, the jet is really following the nut and not being held up by choke linkage or w-h-y.

 

[JSpears]

Thanks Roger,

I notice that when I toggle the choke, the back jet goes up and down, but the front jet does not move. Is it too tight?

 

[TR3driver]

Something isn't right, as the jet should be pulled up against the nut by the return spring next to the nut. One thing that will help is to remove the jet and polish the surface as slick as you can get it. Ordinary toothpaste on your fingers will do for a polishing agent/tool. Clean it thoroughly before re-installation of course.

There is a fairly delicate balance between the tension of the jet return spring (next to the mixture nut) and the internal spring that spreads the seals against the jet. If the linkage moves freely, but the jet does not return by itself, then I would replace first the return spring and then the internal gland spring.

 

[Adrio]

I suspect Randal has the answer. However, if that does not work, there could be the needle set (or moved) too high such that you can't get the jet high enough (relative to the needle) to get your mixture lean enough.