4K suddenly not idling?

[AGRORB]

Went to service my KE today and on the way home my car has decided suddenly that it doesn't want to idle, and low speed light throttle cruising is quite rough and jerky. I have replaced the plugs, tested for manifold and carb leaks and tried turning the idle up a little, to no avail. I can get it to idle, but after a heavy throttle application or rolling up to an intersection it coughs and dies. Any ideas? There was a lot of fuel vapour coming from the carb when I took the air cleaner off, and there is a vacuum port on the base of the carb that has been blocked off with a screw. Looking from the front of the car, the left side choke (smaller of the two) is permanently closed and no fuel comes from the jet, whereas the right side works normally and seems to spray a fair bit of fuel in. What could be the problem? The green plug to the carb is still plugged in too, btw.

[Dell'Orto]

Did you do any service work to it before it started to do this? Or just randomly started?

[AGRORB]

No I had just gone and picked up plugs and an air filter from repco and was on my way home, was running fine til it felt like it fuel starved, so I nursed it to a gas station and put in a quick $10 of 95 to get me home.

I have removed the fuel filter and plumbed the fuel line directly into the pump, no difference, so that eliminates the filter. Have reconnected the dizzy vac advance property, wound the mixture screw all the way in and about 2 turns back following advice on club-k, throttle response is much better, I have also wound the idle screw in so idle is currently around between 1000-1300 rpm (I don't have a tacho), it's idling BETTER, but is still randomly dying.
Slight jet blockage? Fuel pump on its way out? I can't think of much else it would be... The previous owner said the motors had a "lumpy cam" at some stage although how true this is I'm not sure, before this morning it had a very consistent and clean "pulse" or rut to it which may suggest its had work, either that or it has issues...

What to dooooo?

[Lloyd]

Could just be a little bit of gunk make its way through and blocked up an idle jet. Turning the idle speed up is basically just opening the throttle a little bit and exposing the progression ports and using them as the fuel for idle.

Couldn't hurt to pop the lid off and give everything a decent clean out, likely hasn't had it done in 30 years.

[Dell'Orto]

Yup, I wouldn't be surprised if there is a blockage in a jet somewhere, easy enough to pull apart and clean up

[AGRORB]

Yeah it was a bit manky, will get one of those rebuild kits off trademe and give everything a birthday while it's apart

[Rob]

Do your fuel filter while your at it, I would say it is probably got something to do with that beef

[AGRORB]

That was on my shopping list, but BNT, Supercheap and Repco were all out

Could I just use any random filter? Surely better than what it has...

[Dell'Orto]

You can just use a Z14-15, it won't fit in the bracket but will work perfectly fine.

[AGRORB]

Cheers

[YeMs]

Hold the throttle open, up around 6000rpm, with the air filter housing off, then hold your hand flat over the mouth of the carb and press it down to block the air from going, in as you do this hold the throttle wide open. You will feel it suck your hand onto the carb and the engine will choke. Let it off just before it dies and giv the throttle a jab to keep it running then giv it a couple of blips on the throttle.

This causes a huge vacuum inside the carb and draws any debris through any of the jets and sucks it through the motor. Can do it a couple of times to be sure you've given it your best attempt. I can't guarantee it will work, however I've had a bit of success with it and saves pulling the whole carb to bits.

[AGRORB]

Too late, already stripped it, no car until my parts arrive now as the accelerator pump seal fell to bits when I went to reassemble it... -_-

[allencr]

Hold the throttle open, up around 6000rpm, with the air filter housing off, then hold your hand flat over the mouth of the carb and press it down to block the air from going, in as you do this hold the throttle wide open. You will feel it suck your hand onto the carb and the engine will choke. Let it off just before it dies and giv the throttle a jab to keep it running then giv it a couple of blips on the throttle.

This causes a huge vacuum inside the carb and draws any debris through any of the jets and sucks it through the motor. Can do it a couple of times to be sure you've given it your best attempt. I can't guarantee it will work, however I've had a bit of success with it and saves pulling the whole carb to bits.

x2
Look the jets & check-balls for debris

[AGRORB]

Okay, part 2 of the saga, my idle problem continues, I have the carb fuelling fine all through the rev range with no flat spots, great throttle response etc, but my car still won't idle without several stabs of the throttle when coming to intersections and is very jerky at light throttle just off idle, I.e. pulling into driveways etc...

Any ideas? Scored a Weber DCD, manifold, adaptor and filter for $100 but just wondering is there anything else worth trying before I bin my Aisan and make the change? Its not a slow, spluttering dying, its as though someones just flicked the key off, and as I said fuelling is fine to redline...

[Dell'Orto]

Factory exhaust manifold?

[AGRORB]

Yeah, lot of movement in the engine and exhaust too...

Loose manifold bolts? Haven't checked, its too cold out

Pathetic, a Scotsman scared of the cold

[Dell'Orto]

Possibly, but not likely. Lots of people put Coby extractors on which can cause manifold leaks, stock is usually pretty good.

[AGRORB]

Hummm... I've just bought a set of Cobys too :/

[Dell'Orto]

You'll either need to get the manifold faces machined so they're the same thickness (inlet is 12mm IIRC, Cobys are 10) or make a stepped washer to hold them on tight.
As for the stalling issue - have you fiddled with the idle mixture screw much? Ignition timing is spot on?

[AGRORB]

I can wind the idle right up til it's impractical and still have the same issue, I'll borrow a timing light and see where I get, that's the only aspect of the ignition side I havent checked, all physical components are in good working order though. I've pretty much gone through everything I can.think of with the carb including another tear down and clean, to no avail...

Wouldn't be a float level issue would it?