Over fuelling problem

[Betared]

After several months in lay up I decided to make a start on tidying up my 1983 2000 Coupe ready for the spring.First problem of course was getting it to start but after much cranking and two batteries later success! However this was short lived as it quickly became apparent that the engine was running overly rich.Screwing in the idling adjustment screw fully had no effect.A strip down and jet clean was called for, me thinks.I have a small ultrasonic cleaning bath so after removing the cover,jets and floats, into the bath it went and after 15-20 mins certainly looked a lot cleaner inside and out.All passageways were blown through as were jets and holders.I then reassembled the carb. as per the Haynes carb. manual.I also decided to replace plugs,plug leads,distributor cap,rotor arm and the coil for good measure.After replacing and piping up the moment of truth! The car certainly started a lot easier but again its running far too rich even with the idling adjustment screw fully home.
What an I missing, apart from my hair? Any thoughts anyone?
David,

[peteracs]

Hi David

Problem with carb flooding due to faulty valve or blocked return pipe to tank, air filter clogged/damp?

Just first thoughts!

Peter

[Betared]

Hi Peter, I'm testing without the air filter fitted, I've disconnected the fuel return at the carb. and let it run into a container and there's no change, and I've fitted a new float needle valve assy although that may not be seating properly. Is there any visible sign when looking into the carb that it is flooding?
David.

[Neil-yaj396]

What are the symptoms of over fuelling that you are seeing? Normally, after long lay ups, these carburettors under fuel due to blockages.

[rossocorsa]

Just curious, was this car originally an i.e. as an 85 with carb is a bit of an oddity?

[Betared]

Neil, After starting I have to hold the throttle open to maintain revs otherwise it just dies, there is a strong petrol smell from the exhaust and the plugs soot up very quickly.
Alan, my mistake , the car is actually an '83 Volumex shell into which the previous owner had fitted the 2000 carb. engine.
I have a spare carb. which I have also overhauled and will try on tomorrow. One curiosity I noticed is a difference in the shape of the idle mixture control jets. One is tapered and the other has a step in the taper. I assume they are interchangeable between both carbs as doing so doesn't make any difference to the running.
David.

[rossocorsa]

Is it using the mechanical fuel pump or the electric one of the VX?

[Betared]

All the mechanics are as per the carb car. Am I correct in thinking that with the idle mixture screw fully home the car shouldn' idle.
David.

[rossocorsa]

Hmm I'm not sure but it wouldn't idle very well, I'm not very good with carbs and carbs from this era often have extra sophistications for emission control. Have you checked of the auto choke is switching off correctly?

[Betared]

The choke does close up as per normal but I have to keep the throttle held open to get extra air to burn the excess fuel and when the choke is finally open keep the throttle open to maintain the revs.
David.

[rossocorsa]

Some of these Webers from this period gave both an air bypass screw and mixture screw, just a thought

[Betared]

Thanks for your input Alan. There's no air bypass evident on my carb. i'm going to fit the spare tomorrow and hopefully have some success.
David.

[rossocorsa]

It is a bit puzzling, hope it works

[Betared]

Success !! After fitting my spare carb the initial start up looked promising.The car was idling about 1200 rpm initially and while waiting for the choke to come off after 3-4 mins. I noticed that the secondary barrel was swimming with fuel and the engine started to hunt and died. It looked like the fuel shut off float wasn't operating properly. Anyway off came the top, and when I removed the needle found a small piece of paper had got in the housing and was preventing the valve from closing.Don't know where the paper came from as I hadn't used any to clean the carb. Anyway the carb was rebuilt and after starting up and warming up I managed to adjust the idle speed via the mixture control screw which I hadn't been able to do with the first carb. Now I'll have to strip down the first carb again and see if there's any explanation for my initial problem.
David.

[peteracs]

Hi

Congratulations, it is very satisfying when you can actually see positive progress!

It would be interesting to know what you find on the first carb, I suspect a good clean may be a good way towards sorting it given it standing for a while.

Peter