Hi everybody!

I am new to the world of Skoda and cars with carburettors, so I hope that some of you might be able to give me some tips where to look for possible problems on my Forman.

I bought the car last week off a very nice old man in a village. Tested it for 15 minutes and it ran great. It has some rusty patches, but the substance on the "important" parts looks good. Also has a almost new MOT.

I read a lot about the 1.3 engine up front (also here in the forum) so that I know what to look out for. The coolant looked brownish, but there was no mayo in it and the oil looked alright. A little mayo on the Oil filler (don't know how you call it in english) but the guy only drove it to work for 10 km a day, so that seemed legit.

So I bought it and drove it home (around 60 km), checked oil and coolant on the way, everything was working fine. When i arrived at home, I noticed that it the idle was really rough. The car was jumpig a bit from it. On the next day I took another drive, around 20 km, and then the car started stalling when stopping on lights. Back home i noticed black smoke from the exhaust and a biting smell of fuel also in the car. I looked around and noticed that there was fuel leaking on the gasket between inlet manifold and carb. I checked the oil and noticed that it looked very thin, also there was more oil on the dip than before.

 

So my theory is that it was just flooding everytime when it stalled and the fuel just ran into the oil.

 

So my question is: Can a leak in the gasket between carb and inlet (it would be vacuum leak right?) cause the engine or carb to flood?
I ordered the gasket already (spare parts are easy and cheap here in the czech republic) but now I am a bit afraid that it could be the carb itself making troubles!

I was hoping to find some answers here, because it looks like some of you guys know your ways around this engine :)
 

Also please shoot all your thoughts, I am eager to learn about it, i was just hoping to not have a problem with the most complicated part of the car (the carb) after not even a week :D

Thanks in advance!

46 minutes ago, NichiBlembom said:

So my question is: Can a leak in the gasket between carb and inlet (it would be vacuum leak right?) cause the engine or carb to flood?

Of course. The fuel level in the float chamber will be disturbed causing a fuel flood.

The carburetor on Favorit is highly dependent on the vacuum. The seal below the carburetor is crucial. Any minor vacuum leak will make you very unhappy with the car.

 

Tips

1. You ordered the seal you say. There are two seals on the market. One made of steel encased in rubber and the other looking like a sandwich of one steel plate and two plastic spacers with cardboard gaskets in between. Depending on your luck, the seals might be flat. The base of the carburetor might be flat. The top of the intake manifold might be flat. Don't assume they are perfectly flat. Check.
2. Don't overtorque the four screws that hold the seal and the three screws that hold the carburetor on top of the seal. 8Nm is the correct torque.
3. You can check for vacuum leaks in two ways: having air filter off, listen on top of the carburetor. A constant hiss of air is OK. Any gurgling or snoring-like noise is bad. Another option is to use butane gas around the seal and listen for idle increase.
4. Ideally you should strip and clean the carburetor. Some inner channels or jets might be dirty or clogged. I would also replace the accelerator pump diaphragm and the enrichment valve diaphragm located on the side of the carburetor.

 

Hi RicardoM!

Thanks for the quick reply!
 

26 minutes ago, RicardoM said:

Tips

1. You ordered the seal you say. There are two seals on the market. One made of steel encased in rubber and the other looking like a sandwich of one steel plate and two plastic spacers with cardboard gaskets in between. Depending on your luck, the seals might be flat. The base of the carburetor might be flat. The top of the intake manifold might be flat. Don't assume they are perfectly flat. Check.

Thats a great tip, I will check everything for flatness!

I ordered the rubber seal from a Skoda geniune parts wholesale. Is there a risk of it being warped? How could I fix it if it is?
 

31 minutes ago, RicardoM said:

4. Ideally you should strip and clean the carburetor. Some inner channels or jets might be dirty or clogged. I would also replace the accelerator pump diaphragm and the enrichment valve diaphragm located on the side of the carburetor.

 

I am somehow trying to avoid stripping it down myself. Even though I rebuilt carbs for mopeds, I think that this one is an especially complicated one and I think this is beyond my mechanical skills to get it back together and running. Thats why I asked if the seal could be the issue, so I can try myself and if it doesnt bring the solution find a machine shop or a more skilled mechanik who could rework the carb for me and ideally give me an introduction in what to take care of, when doing so.

 

 

Thanks for the help so far!
I want to replace all fuel lines in the engine bay, just to be sure and have ordered a new pump aswell (it costs almost the same as the diaphragm)

9 hours ago, NichiBlembom said:

A little mayo on the Oil filler (don't know how you call it in english)

Well, exactly that.

 

26 minutes ago, KenONeill said:

Well, exactly that.

haha alright, looks like we're not that different after all!

12 hours ago, NichiBlembom said:

I ordered the rubber seal from a Skoda geniune parts wholesale. Is there a risk of it being warped? How could I fix it if it is?

Well, I've seen all sort of seals. Some cheaper ones from VIKA are a disaster both in terms of flatness and rubber resistance to fuel. You can't do anything to straighten them. Hopefully the rubber ridges of the seal will compensate any defect.

12 hours ago, NichiBlembom said:

I am somehow trying to avoid stripping it down myself.

Sure, I was reluctant at first too then I saw it is very easy. There are videos that explain it. But you might get lucky and get away just by changing the seal, the accelerator pump diaphragm and the enrichment valve diaphragm.The latter could flood the engine if it is faulty. By the age of the car I'd say there are high chances to be crispy.

7 hours ago, RicardoM said:

Hopefully the rubber ridges of the seal will compensate any defect.

 

Do you think that some liquid gasket added on top of the rubber could be harmful? If not, I could add some, to be even more sure that it seals?

 

7 hours ago, RicardoM said:

But you might get lucky and get away just by changing the seal, the accelerator pump diaphragm and the enrichment valve diaphragm

 

I found a spare enrichment valve in a box of spareparts i got with the car. It is not brand new, but it looks definitely better than the one thats installed right now. So I will exchange it tomorrow with the baseplate.

 

Regarding the accelerator pump diaphragm: there are no Parts available right now. I had to order the whole thing. Still waiting for it, until then I will just hope that it is not faulty and will just work.

Thanks for the help so far! I will let you know, once I get some results

6 hours ago, NichiBlembom said:

Do you think that some liquid gasket added on top of the rubber could be harmful? If not, I could add some, to be even more sure that it seals?

The liquid gasket is the secret weapon for sealing. Apply it and let it cure as indicated on the tube. I have used Victor Reinz sealant called REINZOSIL with great success. It is fuel resistant, temperature resistant.

Quick update!

I received the accelerator pump yesterday evening, so I couldn't wait any longer, went to the car - took out the carburettor, exchanged enrichment valve and accelerator pump  with all the seals (when I saw them, I understood what you meant when you said that they are crispy haha), put it back together with the new baseplate. I let the liquid seal dry overnight. This morning I went down and fired it up - it cranked for like 30 seconds and after that it fired up und purred like a cat again! no weird shaking, no black smoke!  

 

I ordered oil, filters and new sparkplugs online (it wasn't available at the local carshops), so hopefully I will be able to pick it up and do a service on monday and then take it for a spin and see if it stays healthy after reaching operating temperature!

Thanks so much for the help RicardoM!

You're welcome. The moral of this topic is this: The vacuum seal on Felicia/Favorit cars with carburetor is crucial. It makes the difference between loving your car to death and wanting to ditch it and set it on fire...

Continue with replacing the fuel hoses and basic tuning as mentioned. If in doubt on anything about the engine, post a topic in here. Have a look also in

https://www.briskoda.net/forums/forum/178-classic-skoda-guides/

for gathering more knowledge.