Running very rich (3 x su's)

[jagman1970]

Dear all

My car is running v. rich at the moment. The end of last year I allowed someone to start the car and they pulled out the choke out further than normal. I have had this problem since. What I've done is as follows.
Check float levels (all ok) checked points gap and static timing. Removed the dashpots and reset the jets (all to 75 thou). Check the operation of the choke linkage and its as it should be. Jets move when cable is pulled and return to the correct position when cable is returned. Dashpots not sticking. Slow running set with a carb sync.
The problem is with all 6 plugs so what Have I missed or could check.
Many thanks for any advice or tips.

Keith

[abowie]

How have you ascertained that it is running rich?

[jagman1970]

All 6 plugs are very sooty. Not just black.

Keith

[Heuer]

Something common to all three carbs then which points at the choke given what you have said. On the other hand you make no mention of adjusting the mixture in the approved manner or with a Colourtune.

[jagman1970]

I adjusted the mixture by setting the jets to level with the bridge then turning the screws 2.5 turns (as per manual). I then fine tuned them using digital depth gauge to set all at 75 thou.

Keith

[Heuer]

Very laudable but have you adjusted the mixture using the method described in the Service manual? i.e adjust the mixture on all carbs "until the fastest idling speed consistent with even firing" is achieved. This is then checked by lifting the piston at the side of each carb:

[malcolm]

I set the mixture on my carbs according to the handbook - fastest idling speed etc. Runs really well, nice tickover at the right speed, no snatching at low speeds, no missing, good fuel consumption - but the plugs are always still sooty! So doesn't necessarily mean you're running too rich maybe?

[abowie]

If you have access to a carbon monoxide meter check the CO in the exhaust at idle. Around 5% is where you want to be.

Gunson make one for about $200.