Technical panda 750 young - black smoke

[crimg13]

Hello everyone,

I own a Fiat Panda 750 young, carburated with OHV engine.
On Monday I tried to get it " mot'ed ". It failled with a spectacular 13% CO on tick-over!! The mechanic tried to fix it by fully closing the fuel needle but the CO was still 7.5% (1.5 times above limit).
After that I thought I should clean the carburator, hoping to make it work better, but it only became worse!:bang: Now there is a lot of black smoke coming out of the exhaust and the car goes awful.
The car is great fun but the engine makes me mad! I'm desperate. Does anybody know what can cause this? Any advise will be helpfull.

 

[VmanC]

The air filter could be blocked, try running without it to see if it improves. Also, the needle valve in the float chamber could be seating poorly causing the carb to flood.
Those are the obvious things, maybe check the choke is coming fully off.

 

[crimg13]

The smoke is with or without air filter and the choke is fully off. I checked the needle valve when I opened the carburator (for the second time, thinking I did something wrong) and it seemed to be working fine. The car has 63000 miles on the clock..

 

[james2609]

The air filter could be blocked, try running without it to see if it improves. Also, the needle valve in the float chamber could be seating poorly causing the carb to flood.
Those are the obvious things, maybe check the choke is coming fully off.

I was going to say the same thing about the air filter.

Black smoke is normally due to poorly burnt fuel.

Thoroughly check your ignition system and ensure you're getting a good spark. Could be coincidence that while working on the carb, something else has gone slightly wrong.

 

[purple haze]

or oil getting passed the valve guides and burning off...what do all the spark plugs look like?