P1800s idle issue

[Warrington Dave]

Greetings
I hope this finds you all well?
After battling with my 1967 P1800s I have decided I need some help.
The car starts ok and runs ok on the choke....as soon as I push the choke in the engine revs slowly drop and then the engine stalls.
I have tried 'blipping' the accelerator as the revs down but it doesn't make any difference.
I have done the carb balance....colour tuned the carbs......both seem ok but the problem continues.
Anybody and ideas.......any help gratefully accepted
Dave

[Burdekin]

How have you set the idle mixture and idle speed? Did you follow the service manual?

[VolvoRoyS]

What happens if you pull the choke out again?

[Derek UK]

Is there any looseness at the throttle shaft and carb body? If it is any more than a very tiny amount, virtually imperceptible, you will always have difficulty getting a reliable idle. The looser it is the worse it becomes.

[Burdekin]

Originally Posted by Derek UK

Is there any looseness at the throttle shaft and carb body? If it is any more than a very tiny amount, virtually imperceptible, you will always have difficulty getting a reliable idle. The looser it is the worse it becomes.

Good point and also check for any vacuum leaks; manifold/carb flanges, brake booster and look ine etc. But as above make sure you have set the idle as per the green book service manual not by a colour tune. The SU carbs should idel rich at about 13.2:1 fuel/air and if you adjust as per the manual you will be pretty close to this. Also colour tunes I found to be not very good with modern fuels and wouldn't bother with them.