Hello! Once the car warms up, the idle gets rough. Revs start jumping up and down. It got better after I fixed a vacuum leak in the base gasket. (engine dies when unplugging the idle cutoff valve but stays running when the CO screw is all the way in).  Also, I replaced the manifold gasket. The second problem I have is that I believe ice forms in the carb when driving in colder weather. (after about 17 min, the gas pedal stops responding, and eventually, the car dies). I don't have the heater element and it seems to be impossible to get as well but the air intake gets warm air from on top of the exhaust manifold. The last problem is that a lot of white smoke comes out of the tailpipe even when the engine is warm. (I tried changing the head gasket but it didn't change anything).

Edited 27 January, 20251 yr by RalfRannet

6 hours ago, RalfRannet said:

The last problem is that a lot of white smoke comes out of the tailpipe even when the engine is warm.

OK, does it use oil?

I havent driven the car that much, maybe a few hundres km but havent noticed a drop in the oil level. Cant say anything about the coolant because I just finished fixing several leaks. 

Edited 28 January, 20251 yr by RalfRannet

eh its lean, give carbie a clean rebuild

Actually i already cleaned it, im not sure if the problems were there before the rebuild but they are now. Also it didnt pass emissions because it was running too rich.

3 minutes ago, RalfRannet said:

Actually i already cleaned it, im not sure if the problems were there before the rebuild but they are now. Also it didnt pass emissions because it was running too rich.

I agree with @Thefeliciahacker; your description sounds more like it's running lean. It would help if you could describe the colour of the spark plugs' electrodes.

I actually changed the spark plugs a month ago, hoping it would solve the problem so i don't know if it would be of much help. Old ones were black. Also turning the CO screw out (should add more fuel to the mixture) doesnt solve the idling problem, it only seems to get better for a moment.

1 hour ago, RalfRannet said:

I actually changed the spark plugs a month ago, hoping it would solve the problem so i don't know if it would be of much help. Old ones were black. Also turning the CO screw out (should add more fuel to the mixture) doesnt solve the idling problem, it only seems to get better for a moment.

If the old plugs were black, they were oil or carbon fouled. Was it matt powder or oily liquid black?

They were all matt. (meaning that it was running rich?)

rich you say a rich engine is gurgling and sounds deep can we get a clip

Here is a video: https://youtube.com/shorts/wV0-MSAXp7M?feature=share. It isn't heard in the video, but it sorta coughs at idle, stutters a bit. 

Unless you have already done so and the other posters here know about it I think you need to give more information and back story to this.

 

When did this start and why did it start.

 

How long have you had the car and been driving it.

 

What is the service history of the car and what service, maintenance and repairs have you and others made on the car recently and fairly recently.

 

Photos, landscape not portrait where appropriate as that gets more information into the image, of the engine bay and carb.

 

Edited 28 January, 20251 yr by nta16
typo

I purchased the car a few months back (driving back home, it averaged around 7.5 L/100km), and it was already smoking then. After checking the vehicle at a technical inspection place, it ran way too rich. (too much unburnt fuel exited the exhaust). It also started icing (I believe). The throttle becomes unresponsive, the car starts jerking and eventually dies. After a few minutes of standing, it's fine again. So I took the carb apart completely and put in new gaskets. The idling problem was occurring then as well but mostly when the CO screw was turned out only about 2 turns and the car wouldn't turn off when the idle cutoff valve wire was pulled. The base gasket was in bad condition, but I couldn't find a new one, so I used Victor Reinz gasket maker (which @RicardoM recommended in another forum thread). After fixing the gasket, the engine would shut off when disconnecting the wire. Not the same case when turning in the CO screw (it should cut off fuel). It only died when the idle screw was set so low that it just didn't have enough rpm. Also changed the head gasket (quite new looking) and manifold gasket (pretty rough). Before changing the head gasket, some white residue would collect underneath the oil cap after driving (occasionally) but disappeared after standing still for a night. Oil seemed fine. Dont know what was done previously with the car. Only has 100k km. I haven't driven it much, only a few hundred km, since I want to fix it. Pictures are taken without the air filter on. I also changed the distributor cap, spark plugs and wires and the belt.

 

 

 

Edited 28 January, 20251 yr by RalfRannet

@RalfRannet @nta16 @Thefeliciahacker Well, I can't actually prove this over the internet, but I think the carb is very badly set up, and may possibly also have a air leak.

The setup part I'm trying to figure out. The choke works as expected: when cold starting, revs go to 2k and then fall to about 1500, where they will stay at till the engine is warm, then drop to about 800. When adjusting the CO screw, turning out makes it idle better but not that much anymore, when its almost fully in the revs drop a bit and the car struggles to keep the revs. Really starts moving up and down (+-100). (Also happens when the screw is turned out more) Only at idle. I try to adjust the idle according to the mixture. Also read from a forum that running lean may help with the icing but haven't seen any proof of that yet. Starts up well, takes less than a second. Idle is very good as long as the choke flap is closed.

Edited 28 January, 20251 yr by RalfRannet

Wait what you are saying isnt really making sense, if its running better with the choke it means is lacking fuel but yet its running reach. Im not very familiar with the pierburg (and clones) carbies but if I wad to guess something is leaking or folding like not atomizing well enough a warm engine will be much more reluctant to idle super reach

2 minutes ago, RalfRannet said:

Only at idle. I try to adjust the idle according to the mixture. Also read from a forum that running lean may help with the icing but haven't seen any proof of that yet. Starts up well, takes less than a second. Idle is very good as long as the choke flap is closed.

I think you have a clog in the idle orifice

I know that's why I'm asking for help. I do believe that there is a leak. The idle shouldn't be that bad even if it was running lean, I think. I haven't tested the pollution after the rebuild, but the exhaust smells very strongly of gasoline. For the previous reply.

Edited 28 January, 20251 yr by RalfRannet

5 minutes ago, Thefeliciahacker said:

I think you have a clog in the idle orifice

Interesting, I have to somehow test it then. On the weekend when I have time, tho. Any suggestions on how to do it?

 

 

1 minute ago, RalfRannet said:

Interesting, I have to somehow test it then. On the weekend when I have time, tho. Any suggestions on how to do it?

Im not qualified enough when it comes to carbs see and do 

8 minutes ago, RalfRannet said:

The setup part I'm trying to figure out. The choke works as expected: when cold starting, revs go to 2k and then fall to about 1500, where they will stay at till the engine is warm, then drop to about 800. When adjusting the CO screw, turning out makes it idle better but not that much anymore, when its almost fully in the revs drop a bit and the car struggles to keep the revs. Really starts moving up and down (+-100). (Also happens when the screw is turned out more) Only at idle. I try to adjust the idle according to the mixture. Also read from a forum that running lean may help with the icing but haven't seen any proof of that yet. Starts up well, takes less than a second. Idle is very good as long as the choke flap is closed.

Ok, I've never had a carburettor car rev that hard (2_000 or so) on a cold start and full choke.

 

I also never adjust mixture or idle stop until the engine is full hot, say after 10 miles (16km) at highway speeds.

 

Reference the carburettor icing, this can occur any time you get very high relative humidity, and is more likely if you have the intake set to "Summer" and/or missing/broken "Winter" ducting.

Just now, Paws4Thot said:

Ok, I've never had a carburettor car rev that hard (2_000 or so) on a cold start and full choke.

 

I also never adjust mixture or idle stop until the engine is full hot, say after 10 miles (16km) at highway speeds.

 

Reference the carburettor icing, this can occur any time you get very high relative humidity, and is more likely if you have the intake set to "Summer" and/or missing/broken "Winter" ducting.

The choke is automatic and according to the Pierburg manual, it is supposed to be 2000 +-200, (mine is a clone: Jikov 28-30). I can adjust it tho. I also adjust the screw when the engine is warm, the temp gauge is in the middle. The air intake has a flap inside that should open at 70 or smth degrees and let in colder air. When it's closed, it can only pull warm air from on top of the exhaust manifold (a pipe goes there). It's warm to the touch, including the air filter housing. 

9 minutes ago, RalfRannet said:

Interesting, I have to somehow test it then. On the weekend when I have time, tho. Any suggestions on how to do it?

 

 

Have a good look at the top surface of the carb. The circular brass bits are the top of the emulsion tubes. There should be a tiny air orifice in each. There may be debris blocking the idle one.

15 minutes ago, RalfRannet said:

Interesting, I have to somehow test it then. On the weekend when I have time, tho. Any suggestions on how to do it?

 

 

Zooming way in on your photo, I think the idle one is the one with slots that could allow a screwdriver to unscrew and remove it.

Thank you for clarifying, but both of the holes were clean.