TR6 Carb Mixture

[daverosscohen]

It seems as though the carbs are running lean. (when i lift the piston, car bogs down and wants to stop) but with my mixture tool, it seems as though i'm as rich as it'll go. Do i need a new needle?

 

[Brinkerhoff]

You might have something else going on , like a vacuum leak , low fuel level in the float bowl , bad diaphragms etc. you probably should switch to a richer needle anyhow what with the new blends of gas and all.

 

[TR3driver]

More likely means you've got a small vacuum leak somewhere. But the mixture adjustment was deliberately somewhat limited, and the later cars were supposed to run lean at idle. So you may not have a problem at all.

BTW, it can't be the needle making it too lean, unless you've made other modifications to the engine. They can only wear towards rich.

 

[poolboy]

Put the needles in the middle of their adjustment range, about 1&1/4 CCW from fully CW.
Go for a long drive..30 miles or more with as little stop and go as possible then pull your spark plugs for a better indication than the lift the air valve technique.
If you can't take that drive because of the weather or whatever there's no use in worrying about the mixture until you can.

 

[glemon]

I am with Poolboy on this one, every Haynes manual I have ever seen has the picture of the various plugs on lean and rich motors, and I am sure there are various online sources as well. Also how is it running, a lean engine takes a lot longer to warm up and take throttle without stumbling, if on a cold day it takes forever or never gets to a point where it takes throttle without a stumble, it is likely too lean, if on a cold day (say below 40F) , cold start up, it immediately can take full throttle it may be too rich.

 

[daverosscohen]

Good stuff to think about. Thanks gents. Will report

 

[DougF]

Has the engine had these symptoms for a long time or have they just become noticeable of late?