Hello everyone,

As the post says, I think I'm having a carburettor issue (Vacuum leak??), at least that where everything is pointing to. Let me give you a bit of a background.

So I bought a Škoda Favorit 136L past summer, and it wasn't working correctly, so me and my friend decided to try and fix it. We bought a lot of parts for it and fixed almost all of the issues that it had. We changed back shock absorbers, timing chain, brake oil, transmission oil, carter gasket, spark plugs, alternator, starter motor, oil, antifreeze, adjusted the valves etc... you get the point (almost everything was replaced) When I first bought the car the carburettor wasn't adjusted correctly, but at the time we didn't know what was the exact issues so we just increased the idle speed on the careburettor (because the car was stalling in idle). Now after months of work on the car we decided to take the careburettor out and clean it. We did so and since we placed it back we are having an issue with the carb itself constantly and we can't understand what the issue is. At first we thought it might be the ht leads and the distributor timing, so we checked that out (distributor was slightly out of spec, so we fixed it), but the car continued to behave weirdly: The car is behaving very similarly to this one in the video: https://www.youtube.com/watch?v=5VZBIrH_F-o . Now as RicardoM suggested in this post: https://www.briskoda.net/forums/topic/367304-skoda-favorit-pierburg-puzzle/ we used Reinzosil with gaskets (left it 24 hours to dry before staring the engine up (a couple of times)), we also unplugged the 1-pin connector that feeds the carburetor shutoff valve (and the car immediately stalled), also tried to screw in the mixture screw all the way but the issue remains the same, now I'm kinda crazy at this point because we basically tried everything, yet the car is still not working properly (as I wrote above, almost everything was replaced and the car was working more or less fine before we took the careburettor off and cleaned it. Are there any suggestions? We now think that maybe the mixture screw is off and potentially the idle speed screw as well (when ever we were turning those screws we returned them back to the position that they were in) Any help we can get will be much appreciated.

Edited 25 March, 20251 yr by Joja2k

Hi, welcome.

There have been a couple of threads recently with lots of info and advice, take a look at those and relevant past threads.

Then check everything again, have someone else check they might see what you've missed. Go through the order of set up and check all settings in order, start at start and move on in order of checking don't go out of order or skip. before moving on to next

Have you tried removing the oil filler cap when the engine is running and fully warmed up and see what happens, same for petrol filler cap.

51 minutes ago, nta16 said:

Hi, welcome.

There have been a couple of threads recently with lots of info and advice, take a look at those and relevant past threads.

Then check everything again, have someone else check they might see what you've missed. Go through the order of set up and check all settings in order, start at start and move on in order of checking don't go out of order or skip. before moving on to next

Have you tried removing the oil filler cap when the engine is running and fully warmed up and see what happens, same for petrol filler cap.

Can you please pinpoint to those posts? Cheers!

As there is so much to know about you, the car, the history, what was done (I know you have given some details) and the other carb queries and issues my not be 100% directly related to your and as there are so many possible posts I will just find the threads for you to go through and take as much as you want or think you need.

I will be back and post the hyperlinks in a post for you.

Also what can often aid trying to sort stuff like this over the internet rather than in person with the car, good (portrait mot landscape as generally more information that way) photos of the carb and engine bay or a video if you want to. Other general information possibly related to the issue can also sometimes be seen.

Not all original posters return to post what the solution was, perhaps they still have the problem or just forget after it is sorted, there may still be reports in the thread(s) of what does and does not help resolve the particular issue to the subject of the thread and car. Cars of this age can have a lot of variation from factory original from past and current owners which sometimes are known and others not and not always mentioned in threads or perhaps revelled from photos or posts. The basics of course remain the same and best to do diagnostics and checks from the start of a clear path and not to assume but always check, and double check, tests to confirm and cross reference. Sod's Law often applies and the thing(s) that "can't be" the cause can be and things "already checked" or "don't need checking" need checking and rechecking and parts that "are good" and"fully working" turn out not to be.

HTH.

https://www.briskoda.net/forums/topic/531162-felicia-13-engine-stalls

https://www.briskoda.net/forums/topic/529879-skoda-felicia-13-carb-only-idles-well-when-choke-flap-is-closed-and-a-few-more-problems/

https://www.briskoda.net/forums/topic/529455-skoda-favorit-stalls-and-wont-start-after-running-for-couple-of-minutes-after-a-cold-start

Edited 25 March, 20251 yr by nta16

Hello again, after a long time of trying everything that I could again and again. I ordered replacement gaskets for the carburettor together with the new plastic spacer from vika (the finish of the spacer plate was pretty bad) I sanded it down to be flat, sealed it up with reinzosil and a new gasket and left it to cure for 24 hours straight. Then I started up the car and it pretty much worked as it should, a couple of days later a started to notice a strong petrol scent in the cabin, so I took the carb out again and it turned up to be the float needle, so i replaced it and when I put the carb back together and started the car it started to behave like it had a vacuum leak again (I was pulling my hair out at this point (needles to say I was pretty ****ed)) So anyway I improvised a smoke machine but when I used it there was absolutely no smoke coming out of anywhere (meaning the seal was good) So I decided to screw the mixture screw all the way in, but the car kept running (when I screwed in the mixture screw I counted as to how many turns I made) And after a couple of minutes of runing like it had a vacuum leak, I returned the mixture screw back to it's position and voila! The car somehow started running buttery smooth. I said to myself: "**** it, that's it! It works!!" . And so I decided to close it up and not touch it again. And still today, the car is running smoothly!

Cheers!

Thanks for reporting back. **** parts quality is just restricted to Vika and spacer (insulating?) blocks, gaskets, or possibly any other new parts you fitted. Fully going through the range of adjustments might have cleared a bit of grit/****/debris/swarf, cleared something or smoothed something, or anything else you done this time - who knows, just rejoice!

Well done, you got it sorted by keeping going at it.

Often things are speeded up greatly when not dealing with modern made parts, if you can get good quality New Old Stock original, second-hand or good quality reconditioned/refurbished parts then often they can be better. Buying cheap can be very expensive in costs of time and hassle and replacing the cheap parts.