Running mega RICH, help me with my carb please :(

[HULK]

Right i`m running really very rich,The sparkplugs a black and sooty and now when i turn the engine off after a drive it will backfire the unburnt fuel in the exhaust, how do i adjust the carb to adjust the fueling, is it the mixture screw?? which way do i turn it to make it leaner,:confused:
Also my idle speed has dropped lots to the point where the engine conks out even when warm, what has caused this???:scratch:

any help would be great??:agree:

[Markey Mark (BD)]

The mixture screw will only adjust the fueling on idle, the jet sizes comtrol the fueling while driving.
Do you know the jet sizes or who done the carb originally if it has been re-jetted?

Also, take the lobster top off with the engine running and see if you can see fuel dribbling down the venturi while its running.

[Spooky]

What is the carb jetting ?

Is the main jet bigger than 1.2mm?

[Spooky]

The mixture screw will only adjust the fueling on idle, the jet sizes comtrol the fueling while driving.
Do you know the jet sizes or who done the carb originally if it has been re-jetted?

Also, take the lobster top off with the engine running and see if you can see fuel dribbling down the venturi while its running.

:D :agree:

[HULK]

The mixture screw will only adjust the fueling on idle, the jet sizes comtrol the fueling while driving.
Do you know the jet sizes or who done the carb originally if it has been re-jetted?

Also, take the lobster top off with the engine running and see if you can see fuel dribbling down the venturi while its running.


I dont know what size jets are in the carb, previous owner (jesus) has told me that they should be standard jets.

Noticed at the weekend,while engine was off, i took off my lobster and pressed the accelerator cable, fuel squirted out of the emulsion tube in a straight line, but after a few more presses of the throttle it stoppped coming out, sometimes it dribbled

also i cant look in the carb with the engine running as by the time i have got out the car and looked at the carb the revs have died and the car has conked out :cry:

[Markey Mark (BD)]

Clean out the idle jet (big brass screw on side of carb) and see if it idles better.

[HULK]

Thanks Mark, i will do that next, I turned the idle speed screw clockwise one full turn but it made no difference :scratch:

Does that screw actually do anything???

[Spooky]

here are the jets...check out the picture and get familiar with it :)

Clean out the idle jet as Mark suggested.

Also, try to remove the mixture screw but not all the way out to see if this improves and stabilises the engine idle speed.

If the revs are increasing a little, wind in the idle screw.

Its a case of finding a balance between the mixture screw and idle screw.

If that doesnt work, you may need to look at something else :) :agree:

[jonnyshaw49]

hi mate take the mixture screw out is the end snapped off?? should be like a needle point on the end that sits in a tiny hole in the carb body, make sure the mixture screw is wound out 2 and a half turns from fully in, also is the car running lumpy on idle? check that the little seal is ok around the emulsion tube and intact, check the 2 diapragms are intact in the second stage part of the carb, like already said check you have the standard 120 main jet and standard idle jet and also check if the air corrector jet is not a 0.9 or any of the jets have been drilled bigger, its a case of elimination mate, mine was doing exactly the same narrowed it down to the mixture screw being dodgy even tho it looked ok so just swopped it, hope this helps