WD40 is not a good carburettor cleaner, and sometimes you need to use multiple sessions of carburettor cleaner to remove the sticky varnish from it, The worst is always blocking the air passages in the top hat. Ideally you spray - let alone to soften, scrub with some nylon bristles, use a long one to clean passages, spray again etc.
You may not have used such wire methods but previous mechanics would have, Thats how their ustaads taught them, The distributor vacuum pod is ideally checked with a vacuum pump, or you can push it inward while sucking on the pipe, it should hold vacuum if you block the pipe with your tongue - its only a basic test to show that the pot is holding vacuum, the plate inside the distributor should move with slight resistance, meaning do not bathe it in grease or oil, just enough for it to move easily but with slightly slow movement.
The hot idle compensator is temperature controlled, heat it up and blow through it it should be open, it should be blocked when cold. Its job is to lean out the idle mixture when hot by adding air directly to the manifold.
