Aircooled VW South Africa

As you have the carbs off, put them in the vice or screw them to a plank

Fill you float champers by gravity pipe feed.

Fit fuel line from your pump, and swing the motor

See if the plank gets wet.

If it gets wet, it is your needle and seats.

If not open top of carb and see where you fuel level sits adjust by taking out or putting in washers.

Try again

Herman

acpaterson wrote: ↑Mon Mar 12, 2018 8:30 am After the umpteenth carb check etc, I also decided to replace all the HT leads and fitted new plugs. I discovered the plug had a broken core, out the box..

Will change out the plugs with new or known working ones and replace all leads and recheck. I think the plug could have been dead already when I swopped the leads on Satruday.

retrovan wrote: ↑Mon Mar 12, 2018 9:13 am As you have the carbs off, put them in the vice or screw them to a plank
Fill you float champers by gravity pipe feed.
Fit fuel line from your pump, and swing the motor
See if the plank gets wet.
If it gets wet, it is your needle and seats.
If not open top of carb and see where you fuel level sits adjust by taking out or putting in washers.

Herman

Washers ??

Thanks Herman, will give it a try.

If the pump is connected to the carb and the bowl is full and the needle seats to not allow any more petrol into the bowl what happens to the pump/fuel that is being pumped ?

Washers under the needle and seat, gives the correct float level.

The pump just maintains the pressure and the needle and seat keep the fuel from coming into the chamber, till you use fuel, then it allows fuel in to the right level, and shuts off again.

Your pump is made to run up on pressure that why it important that the fuel pump is not too high in pressure.

Herman

by wahsers, he means "bend the tab"

Tony Z wrote: ↑Mon Mar 12, 2018 1:06 pm by wahsers, he means "bend the tab"

For a second there I thought Herman was adjusting his fuel levels by chucking in washers into the fuel bowl

Tony Z wrote: ↑Mon Mar 12, 2018 1:06 pm by wahsers, he means "bend the tab"

No he does not...

You take out the seat(unscrew it) and add washers under the valve and screw it back, to drop the valve down deeper into the bowl making the fuel level lower in the bowl.

Bending the tab, could creak the float or angle the tab in such a way to jam the needle.

Old British car had the tab bent, as it was made to do that, but VW has always done it with washers.

Donovan D wrote: ↑Mon Mar 12, 2018 2:39 pm

Tony Z wrote: ↑Mon Mar 12, 2018 1:06 pm by wahsers, he means "bend the tab"

For a second there I thought Herman was adjusting his fuel levels by chucking in washers into the fuel bowl

Would not effect level at all.....

Here you go;--

From Rob & Dave's aircooled Pages. http://www.vw-resource.com/


Needle Valve Washers

A problem can occur if the thickness of the washer under the float needle valve is incorrect, which in turn will make the fuel level in the carburetor float bowl incorrect. The fuel level effects the fuel level on the emulsion tube. The emulson tube works with the air bypass jet and seems to effect the rate of fuel vaporization. This means that the level of the fuel in the carburetor bowl is critical.

If the fuel level is a little low in the bowl (washer too thick), then facing downhill and cornering will cause the engine to run lean, causing stalling. Facing uphill the mixture would be a little richer - closer to normal. If the main jet in the carburetor is a little lean, that would make any bad fuel mixture settings even worse.

Following is a procedure for correctly setting the level of fuel in the carburetor bowl -

Position the car on a level surface (or, if the carburetor is removed from the car, place it so that it is level.

If the carburetor is installed, idle the engine briefly to ensure that the float bowl is full.

If the carburetor is not installed, fill the float bowl using a piece of hose attached to the fuel inlet pipe.

Remove the carburetor upper part and the gasket so that the fuel level can be measured.

The distance from the top of the carburetor body to the surface of the fuel should be 19.5mm +/- 1.0mm.

If the fuel level is too high, use a thicker washer under the float valve.

If the fuel level is too low, use a thinner washer.

Note: Washers are available in thicknesses of 0.50mm, 0.8mm, 1.00mm, and 1.5mm. Several sizes are included in the carburetor overhaul kit. The correct washer for the 34PICT/3 carburetor (per the overhaul instructions) is 0.50mm.


Herman

and Donovan has Weber IDF's which bends the tab...

Sorry Tony, still remember him having VW carbs.

You correct and here is a youtube to tell you how to do it D

https://www.youtube.com/watch?v=54uPwTZ3DJw

Sticky floats seam to be a problem with these so look at the clip below.

https://www.youtube.com/watch?v=Yju2Ex-zc5E

Herman

Thanks for the links and info !

CBPerformance recon I need to adjust to max advance of 34 degrees, which should then be between 12 - 14 BTDC degrees at idle for the dizzy and then check richness. 34 sounds like a lot.

@Tony, what was the reason for connecting these two instead of blocking them off individually ?
Not sure if they are vacuum ports or the air bypass screws. They come out straight underneath the butterfly.

vacuum ports... easier to blank them off like that. You can blank them individually, it'll make little to no difference.

34 does sound like a lot of advance. I've always had good success with 28, but each engine is different so its a trial and error to get it perfect for yours.

Today was the first full day in ages I could spend on the engine.

Rechecked float levels,
Cleaned out the passages with carb cleaner, and got the carb back on. This is carb over number 3 and 4 as it was killing the plugs due to over fuelling.
Linkages are disconnected, swopped some plugs around and pulling leads off each plug does make a difference now.
Balanced the carbs with a snail gauge and rechecked timing at 7 BTDC.
Idling is at 950 RPMS but the idling is still very rough, sounds like a tractor.

I managed to get one of those Gunson Colortune things and tried it out today. I cleaned up all the plugs before starting.
Started at plug 2, the flame was bright orange, indicating a rich setting, couple of quarter turns inwards on the idle screw and the flame went blue.
Did the same at plug 1. Im guessing I am about one full turn out on each screw on this side.

When I pulled plug 3 it was fouled and wet, the thread was also wet. Seems like I have an oil issue going on here. pic below.
Got the gunson in and the flame was orange, it will start going over to blue when there is less than a quarter turn of the idle screw before completely seating.
Same at number 4, starts going blue when less than quarter turn before seating. When the screws were completely seated, individually, the engine tone will drop and start popping out the exhaust.
Number 4 was also fouled and caked but dry.
Not 100% sure how reliable these things are. I rechecked 1 and 2 and the spark was still blue, the plugs were clean with no fouling so def not running rich on 1 and 2 anymore.


At least Im running on all 4 but there is just something at 3 and 4 thats not right which I cannot figure out.

I think thats fuel on the plug you posted.
I've wanted a colour-tune for years, but never found one. Honestly, I havent even thought about it in ages.
If both "ports" on the one carb are running rich, then I'd double check the float levels and make sure the needle&seat are sealing properly. But before doing that, pull the idle jets and make sure they are in fact the size that you think they are. They might have been bored out previously or just stamped wrong when made?
If definitely sounds like you are starting to get somewhere now.

Tony Z wrote: ↑Sun May 06, 2018 6:54 am I think thats fuel on the plug you posted.
I've wanted a colour-tune for years, but never found one. Honestly, I havent even thought about it in ages.
If both "ports" on the one carb are running rich, then I'd double check the float levels and make sure the needle&seat are sealing properly. But before doing that, pull the idle jets and make sure they are in fact the size that you think they are. They might have been bored out previously or just stamped wrong when made?
If definitely sounds like you are starting to get somewhere now.

Will swop the needle&seats today and see what happens. I do have jet gauges and all 4 idle jets are between the 50 and 55 gauges. The jets are marked as 52.

Got the Gunson from machine mart UK, just bought it online and sent it to some UK mates, they posted via post office. Works out a lot cheaper.

Nooit man.

Remove these unreliable parts and put back the original, problems will be solved.

sean wrote: ↑Sun May 06, 2018 8:49 pm Nooit man.

Remove these unreliable parts and put back the original, problems will be solved.

Ja ,Im just about ready to do that.



...Removed both needle&seats yesterday, 3 and 4 did look as if it was not seating correctly. It was just not going in all the why as 1 and 2 was.
Swopped the needle&seats around and then had to reset the float heights, 14mm against BB and 23mm full drop.

Got the gunson in on all 4 plugs again, managed to get all the spark color to a nice blue. Im now between 1/4 and 1/8 turn out before the needle is fully seated. The faulty 'needle&seat' seems to be doing fine at 1 and 2.

Balanced the carbs again and rechecked timing, now the idling as at 1200rpm and 1 and 2 side cant come down, the idle speed screw can be completely off the lever and it does not make any difference, 3 and 4 can go down. If I rev up the engine it also does not immediately come down in rpms.

Just before calling it a day I pulled all 4 plugs and all 4 plugs were clean, no petrol no build up clean.