Peirburg 2e3 problem

[project25]

Hi, I notice there are a few threads on this carb, but dont seem to be my problem.
Ive got a 1982 dg 1.9 with auto box. It starts fine on choke, but as it warms and the choke comes off, unless I keep my foot on the gas it will stop. Its not firing on all cylinders, plugs are completely sooted.
Ive checked timing, compression test was 145 psi except for no1 cylinder at 115, changed plug leads, cap, plugs, so Im fairly sure that it isnt electrical. That only leaves the carb.
I read on on archive threads about flooding, so looked at fuel return, thats fine, ran it with air cleaner removed and watched choke doing its stuff. Still sounding like a 2 cylinder stationary engine at a steam show.
Got any other ideas?

[col.decker]

sounds just like mine and I'm doing a compression test this afternoon. But looking at your 145 vs 115 I'd say that you've got a compression problem too, which is what I expect to find in mine later.

Cracked valve or ring in cylinder No.1 for me I think.

I've changed all the same stuff as you too, but I'm doing the fuel pump today too.

[project25]

Im fairly certain that the difference in no1 cylinder wouldnt affect all 4 plugs going black and chugging like a dumper truck.? or could it.

[col.decker]

Don't know really, I'm just working through the list of suspects lol. I've got sooty plugs too

[kevtherev]

Hi, I notice there are a few threads on this carb, but dont seem to be my problem.
Ive got a 1982 dg 1.9 with auto box. It starts fine on choke, but as it warms and the choke comes off, unless I keep my foot on the gas it will stop.?

Reads like you have developed an air leak.
once the choke comes off it will weaken the mixture and stall an engine
plug colour is meaningless unless they are checked after a high speed run

plenty of posts about this problem.

should the air leak prove not to be the problem then fuel delivery is.
pump or filter(s)

[ghost123uk]

My guess is this = If it is running too rich whilst on the choke, then it will soot up the plugs. This causes them (2 in your case) to stop firing. This stalls the engine.

I recently had exactly the same.

I did get advice on what to check (thanks Kev ) but for now I have wired the choke open and along with a set of new plugs the problem has gone away. I will do as Kev suggested and fix it properly when the rain stops !

May I suggest you do the same, just to check. You will need new plugs anyway, so whilst fitting them, wire the choke open. It hardly makes any difference to starting, you just pump the throttle a bit (to richen the mixture with the accelerator pump jet) whilst starting. Mine drives away quite happily after just a minute or so.

[Ralf85]

Could be an air leak. Plenty of options. Have a look on the wiki under 'Fuel system' and then 'carburettor air leaks'

[ghost123uk]

Hang on folks, =

plugs are completely sooted.

Not normally associated with a weak mixture from air leaks ?

[kevtherev]

Hang on folks, =

plugs are completely sooted.

Not normally associated with a weak mixture from air leaks ?

misfire caused by a weak mixture will soot a plug.
the plug colour after the choke comes off will be sooty,
The main jets are on a different circuit to to idle jets.
plug colour is meaningless unless looked at after a high speed run, then you can determine whether it is rich or lean
mixture can only be accurately determined by a gas anyliser at idle speed

[project25]

Hi, thanks for replies so far, Im abit confused about the talk on air leaks. To my mind I have too much fuel or it isnt being burnt properly. When throttle is increased there are back firers. It is definitly not running on all cylinders. As I said I started it this morning without the air clearer on. Started beautifully then started choking, so I held the throttle open to keep it running and watched the choke open as it should. When that was open it was in chugging mode and would not stay running unless I pumped the throttle.

[kevtherev]

what you describe is a classic air leak issue.
pumping the throttle activates the accelerator pump which chucks neat fuel into the venturi.
backfiring is a symptom of a weak mixture.

But you have made your mind up so you must pursue your own therory.

[kevtherev]

to go to your original post

It starts fine on choke, but as it warms and the choke comes off, unless I keep my foot on the gas it will stop.

the choke enriches the mixture, any air leak is negated by this...until the choke comes off.

Its not firing on all cylinders, plugs are completely sooted.

weak mixture.

I read on on archive threads about flooding,

flooding is caused by the stop "cock" in the float bowl stuck open, wrong float height or over fueling due to choke inoperative