Hello,

 

Just got my -84 Polo Classic together and running. 1.3 HK with Pierburg 2E3 carb. Problem is the rough and dragging sound from the head area, could it be the fuel pump? Took timing cover and other stuff off to make sure there was nothing dragging.

Link to video: https://drive.google.com/file/d/1T3BksxrxnnlufVRbofBAx6PGC6eIEWuC/view?usp=drivesdk

 

Also the mixture screw on the carb doesn’t seem to have any effect to the car running. How much should it affect (on idle) when screwed almost fully in vs almost fully out?

 

Pardon my English, cheers from Finland!

Sorry could not play the .mov file.

 

The idle mixture screw should affect the running.

 

As it does not, that likely means you are running on a progression hole because the throttle flap is too wide open, so wind back the idle speed screw to get about 800rpm or less then set the mixture.

 

I'd suggest a Colortune sparkplug, or a vacuum gauge to get a Pierburg 2e3 perfect.

 

Funny noises might be cambelt too tight for water pump bearing.

 

If you can't reduce the speed to 800rpm with the speed screw then you have a vacuum leak. Usually it's at the carb rubber base mount.

Actually found out where the noise was coming. Apperently the fuel pump that the previous owner had got for the car had very strong spring and apperently too long travel . After swapping to an original Pierburg fuel pump from a doner car, noise disappeared. 
 

I’ll check into the mixture problem tomorrow. Actually have a new base mount so that should be fine. I’ll check for any other leaks and try to continue with your advice, thank you! 🙂

Cheers!
 

Car runs very nicely on low rpm. The idle screw still seems a bit weird. Only noticeable difference on the idle speed is when the mixture screw is all the way in. Found out a thread with advice to screw first 1,5 turns out and then start listening when the idle changes. In my case, idle gets worse after one turn. Is that enough? I just want to be sure and not run the engine too lean 😅

 

Hoping to get this thing trough MOT on friday 🤞🏻

Worse after 1 turn is okay. Find the midpoint doing very tiny adjustments (1/8th of a turn). Float might be riding a fraction high so richer.

 

You must setup mixtue at operating temp, but fan off. Let engine warm with bonnet closed.

 

You really only need to worry about lean at high load and the second barrel provides richness for that, automatically by 2e3 pulldown unit; unless you or someone else has changed jet sizes (not easy on Pierburg). Idle mixture is about smooth low speed running (up to 2000rpm) above which primary main jet takes over.

 

Certain the ignition timing is correct?

5° (+or-1) BTDC at 800rpm (+or-50) for HK.

with distributor vacuum hose removed and plugged

(ideally also crankcase breather hose removed and plugged).

 

I can also suggest cleaning the idle circuit.  Maybe this is not needed as runs well

 

Get a length of rubber or silicone hose.

Unscrew the mixture screw completely. Careful not to lose the o-ring on the mixture screw and check it is good condition.

Put the hose in the hole for mixture screw and pump air in (bike pump, compressed air, keyboard cleaner spray or your lungs). It should bubble in the carb well. Then refit mixture screw and try again.

 

Edited 21 July, 20224 yr by dvderlm
static ignition timing

Also make sure choke flap has fully opened to vertical looking from above when engine warm.

 

(and carb earth connection is good so choke heater circuit and part channel heater are working, maybe idle cutoff solenoid if fitted).