TC Stromberg Running Rich

[surypap3]

So still going thru my get-her-running list but making good progress thanks to this forum. The TC with Strombergs is rich at idle. Maybe this is good for the overall engine RPM range. Just don't know. My recall is that the needle can be adjusted by removing the cap/damper and reaching in with an allen wrench to turn the needle up or down as needed. Is that correct, and is there any risk to leaning it out. Thx

[E Paul]

That is the method on the SU carbs. At least on the Z-S I had, the jets were pressed in and not adjustable. Maybe others have different versions. Completely worn out at 30K miles.

[jbcollier]

Early emissions Strombergs had non-adjustable needles.  This is what the Lotus TCs came with.  Triumph TR6s, 7s and 8s had adjustable needles.  You can fit the "piston" from an adjustable carb to the Lotus ones.  With a bit of tinkering you can fit the Euro Lotus Stromberg needles to an adjustable needle holder.

The needle is spring loaded so it constantly rubs against the jet.  As the needle and jet wear, it keeps getting richer, especially at idle.  Might be time for a major overhaul.

HOWEVER

Did you check your valve clearances?  All carbs, but especially CV carbs, run very poorly with tight valves.

More info on Stromberg carb overhaul can be found here:

http://www.lotuseuropa.org/LotusForum/index.php?topic=3619.msg37946#msg37946

[surypap3]

I will have to look. My memory is trying to tell me that when I cleaned up the carbs the needles were adjustables.