How to / DIY > Engines

Lister D Carburettor Strip Down


Good afternoon all

My Lister D project is making steady progress but I am struggling to completely dismantle the carburettor. I want to remove the needle valve and the screw fitting for the spring valve to check they are functioning correctly. Also, I'd like to check inside the float chamber that all is well and cannot remove the inner components. Can anyone advise me please? Pictures attached.

Many thanks.

Ok, I will attempt to make out exactly what you have in your pics.
To me it is not a carby but it is a fuel mixer which means that the large knurled knob on top of the green part in your 1st pic is only a needle valve and should screw straight out. To confirm this turn the assembly upside down and look at the inside where the needle comes down to confirm my theory.

In the second picture that part is for the needle to contact and should not be removed from the float assembly. Again if you look at the green assembly in the 1st pic there should be a needle and seat to control the fuel flow. That is the only part you need to dismantle and clean. Leave the float assembly alone other than lifting it out of the float chamber and cleaning the bowl.

If this is not the case please post more pics of the under side of both assemblies, the float chamber and mixer body. Also if you have trouble removing the main metering needle (the large knob on top) then start soaking the lot in a penetrating oil, diesel or anything to get into the thread to free it up. Electrolysis is also very good at removing rust and freeing up tight screws. Let me know what happens but do not force anything.

Thank you for your kind and helpful advice. The air valve tube - it's stuck but clean and seems to in fine fettle so I'm going to leave it alone.

The float chamber's a bit mucky so I will clean that out and the needle and reassemble.

The needle valve cap came out very easily once I depressed the plunger and as it screws in and out easily - although I can't see it moving up and down in the chamber - I am going to make the reasonable assumption that it is also in sound working order. I will clean it all up and repaint as necessary and reassemble.

The butterfly valve - controlled by the governor mechanism - moves freely so, similarly, I don't see the point in taking it to pieces.

Further thoughts and insights always gratefully received and my thanks again.

Check that your needle and seat function as it should buy blowing into the inlet at the top while pushing the needle up and down. If it starts and stops it will be fine. If you need to adjust the float level and this is a guess as I have no pic of it but you use a flat washer/s between the seat and the housing of the body. If the seat screws in make sure it is firm not too tight  so it wont loosen and drop down onto the float.
Yes, leave the butterfly assembly alone as it is moving so no need to play with that.
Not sure again without a pic what you describe as the 'needle valve cap and the plunger'. So cannot comment.
Does the large knurled knob rotate and able to be totally removed from the body? This is your fuel regulator as I understand it and controls the amount of fuel going into the engine.
Do you have a manual for your engine? If not I generally find them using Google search somewhere. It would be nice if this site had a thread which lists workshop manuals and make it easy for owners to find it an download. There may be one in this Forum but I dont know for certain so maybe ask the Admin for some help.


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