Morris Minor Owners Club

I'm getting sooty (not oil) deposits spitting out of the exhaust once the choke has gone all the way in.

I've tried re-doing the idle mixture from scratch and left it on the slightly weak side. I've also checked the timing (pinking method).

Compression is good(~155psi on all cylinders) and car is running smoothly and evenly and pulls well up hills when out on the road.

This is relatively recent, so almost certainly something that I've done/set incorrectly.

I'm flumoxed, anyone seen this before/got any good ideas please?

unless it is excessive, it may just be 'the time of year'
In winter you'll do more diriving with the choke on (takes longer till warm, therefore more miles with the choke on) - this creates sooty deposits in the zaust.
These get splattered out when condensation droplets pass along the exhaust, knocking the soot from the pipe walls.
So if you do a fair amount of short runs, it's expected to get some sooty splatter out of the exhaust. You get more exhaust condensation at this time of year.

If you do long runs at highway speed the exhaust should get hot enough to remove a lot of the soot.

Right, out for a good blat on the weekend then...weather permitting (still haven't found time to sort my wood)