Car problem - won't idle without choke

[Robby]

Afternoon boys and girls.

Car is a 1984 Honda accord. Straightforward single overhead cam 12v 4 cylinder engine, with a single carb and no complicated electrics. Ignition is vaguely clever, in that it doesn't use points but still has a distributor and a single coil.

Until a few days ago it was behaving well, possibly feeling like it was a bit weak or missing a bit under acceleration. Then I had a little play in it for a couple of minutes and showed it the redline a few times, and it's been running like a pig ever since. It'll idle with choke, with some careful playing I can get it down to 1000rpm but it's hard to hold it there. Push the choke in and it dies right away.

The following have been checked and are spot on:
Valve clearances.
Fuel filter.
Carb cleaned - jets were spotless and no buildup of varnish before I opened it up.
Cam timing and belt tension.
New plugs.

HT leads, dizzy cap and arm are on order, although none of them look too bad.

I'm hoping it's just an ignition problem and those bits will sort it, but if it's a carb problem then it's running lean. Any ideas what the problem could be?

[lonner]

think the prob will disappear when you put the new HT parts on as it sounds like a HT fault

[rottie007]

what colour were the plugs when you pulled them?

personally I would still go with idle jet blocked in the carb, or maybe even one of the passageways in the carb itself leading to it if the jets were clean like you say they were..

also could be an air leak, get it running and try spraying wd40 round the manifold see if the engine note changes?

[Robby]

Fixed.

It was the idle adjuster. No idea how it moved in the first place, but it then partially seized. A squirt of WD40 and a wiggle and I now have a proper idle, accelerating smoothly too.