Club 80-90 Forums

I'm going to be replacing the poor running weber carb on my 1.9 DG engined caravelle with the original pierburg 2e3 once i rebuild it.
I have no idea where the various adjusters should be initially set to get the engine running before i tune it and i don't want to wreck anything.
It was in the spares box when i bought my van and has had the various screws and adjusters fiddled with at some point from the look of it.

Can anyone tell me where the fast idle adjuster, idle speed adjuster and CO adjusting screw should be adjusted (turns out from all the way in would be ideal)?

the mixture screw is useless without a gas analyser.
the tickover screw is at the front under the choke pull down

the fast idle screw ( choke ) should be on the 2nd lobe of the fast idle cam (at this time of year)

choke flap should be closed all but for a gap determined in the Haynes when cold.

suck the pull down pipe to see if it works ok and you can't keep on sucking air
suck the 2nd venturi activating unit on the rear of the cab to see if that works ok
test the accelerator pump on the carb once the float bowl is full, it should squirt fuel into the 1st venturi when the pedal is depressed

just a few items for now

Cheers.

Its just the mixture screw i'm unsure of now. Its currently screwed 1 turn from all the way in (i just put it back to how it was when i got the carb). How far in/out should it be to not cause a mega over weak or rich mixture when i first start it? I just need a basic setting to get it running so i can tune it.

If i can borrow an exhaust gas analyser is it just a case of start the engine up, let it warm up then adjust the mixture screw until CO and HC content are right then adjust the idle speed back to where it should be?
The specs i have state CO @ idle 1.5 ± 0.5 % volume, HC @ idle 300 parts per million, and idle speed of 900±50 RPM.

yes get the gas analyser and do what you said

the higher the CO the richer the mixture is as you know

I have an early DG code engine and would like to locate the mixture screw, the only screw that is adjustable on the carb body is at the lowest point on the right of the carb as you view it from the rear of the vehicle. I've had it on a gas analizer and it made no difference to the CO level (8.3!)
the only other adjustment is the thin rod with a screwdriver slot in the end which adjusts the butterfly stop on the primary choke (idle screw?) which is on the right hand side of the carb. I've stripped the carb and all the jets are clear. any ideas on how to get it down to 4.5 to get the MOT ticket??
regards Gez

Sounds like you've already found the mixture screw (low down on right hand side below where the accelerator connection is).
Have you removed it completely (counting number of turns) and blown through the hole it came out of with compressed air or carb cleaner?

gezvic wrote:I have an early DG code engine and would like to locate the mixture screw, the only screw that is adjustable on the carb body is at the lowest point on the right of the carb as you view it from the rear of the vehicle. I've had it on a gas analizer and it made no difference to the CO level (8.3!)

Then I would suggest there is something wrong with the screw..
did you take it out?
Does the stop "cock" work and not overfill the float bowl

Ain't carbs fun?

Carbs are easy... but folks can't stop twiddling screws even when they don't know what they are or rather what they do.

sussed it ,backed off butterfly screw as it was too far in negating effect of mixture screw. adjusted till lumps disappeared and smelt leaner, back to MOT centre CO reading now 3.2! easy pass
many thanks , holiday road here we come

sussed it ,backed off butterfly screw as it was too far in negating effect of mixture screw. adjusted till lumps disappeared and smelt leaner, back to MOT centre CO reading now 3.2! easy pass
many thanks , holiday road here we come

Great news.