Triumph Repair: Zenith carbs, hydraulic resistance, plastic nut

Question
We have a 1979 TR7 with Zenith CD-2 Carbs. Car runs good but has trouble maintaning idle speeds. I have read where some model carbs require the top chamber to be filled to a certain level with a certain type oil. I have removed the plastic nut caps on ocassion and they have been dry. Last time I checked they appeared to have some gas in there.The idling problem appears to be getting worse. Any input would be appreciated.
Thanks; Brian

Answer
Hi Brian,
The top pots should have oil in them. Engine oil is ok to use. To check to see if enough is in the tube just loosen the screw and lift it up and push it down. If you feel hydraulic resistance it has enough.

The oil is a shock to stop the piston from moving up too quickly on acceleration and to dampen the pulses at idle.

Put oil in and see if it corrects your idle problem. If not you need to run a series of tests on the engine and the carburetors. Let me know and I will try to walk you through the tests.
Howard