Symptom of poor carburation?

[Ian M]

Over the last few days, aided by some quite reasonable weather, I've spent many pleasurable hours working on my Mk1 Ruby. It had sadly languished in the back of my garage for several years, so I'm pleased that I've finally got to grips with it again.

One thing is troubling me and it's not something I can remember ever being an issue with this car before. The engine is quite worn, but still starts and runs reasonably well. However, I am now finding it very hesitant when opening the throttle from normal tickover. It will either stall or require very gentle application of the pedal before the revs pick up.

Any suggestions as to how I might troubleshoot this? I suppose it has to be something fairly rudimentary. Might it be advantageous to get my old carburettor reconditioned while I am at it? Many thanks.

[Parazine]

Old petrol? Even if you've put fresh in, the old fuel in the system can contaminate the fresh, causing a range of running problems.

Only fix is to drain the system, flush properly and replace with a couple of gallons of fresh stuff.

[Nick Salmon]

The slow running adjustment needle will affect tickover AND pickup. Try fresh fuel first. If that make no difference then try altering the needle a quarter turn at a time, testing the pickup response each time.

[Chris KC]

Ian, 

Is it a standard Ruby carb?
Have you disturbed part of the inlet tract?
And does it still do that when the engine is properly warm?

[Ian M]

Thank you, all.

As the fresh fuel is almost certainly mixed with a small amount of old fuel, I suppose the finger of suspicion does need to point there initially. I'll sort that out before doing anything else. The carb is the standard Zenith type.

[bob46320]

I had a similar problem, after 4 years of storage, I filled up with all fresh fuel and all was Ok for 80 miles or so. I was driving from peterborough for Portsmouth en route for SW France, when I had similar problem. First stop was Woking - drained the fuel off and put fresh in. That was good and we got down to Hindhead when the problem came back again. We conked out next to a landcover agent garage. Good bunch there and we blew the jets out, cleaned the fuel pipe (RN with gravity tank) and hey presto on our way again only to stop 4 miles down the road. By this time, we were getting short of time for the ferry, so got a recovery From the AA to Portsmouth and then towed onto the ferry by one of their "tugs" - that was a bit hairy !!
On the other side, a friend trailered the car to home in France. I eventually found the problem to be a worn top bush in the distributer such that the points gap varied from from about 0.006" to 0.018". Further, the distributer drive gear was very badly worn and was replaced at the same time. Why this had not manifested itself before, I do not know, but as you say, started Ok, ticker OK and then sometimes complete lack of power -just a ticker.

[Hedd_Jones]

take the dizzy appart and oil lightly the advance mechanism

[Steve Jones]

But first, do the simple thing and check for inlet manifold/carburettor flange air leaks. These are typical symptoms and given that the car has stood for a long time, exactly what can develop.

Steve