Running issue

RichZ

RichZ

Club Member
Having running troubles. Have had a mechanic with all the proper stuff to check the timing and tune the carbs etc, at idel it runs beautiful checked with gas analyser but when at higher revs it runs lean and won't go. I have had the car running with a much richer mixture and will run fine until the plugs soot up.

Any one got any ideas?

I don't know what needles they are, but needles are probably the thing I know least about.

How hard is it to get hold of the needles?

Thanks for your help in advance. :unsure:
 
It might be little bits of debris in the fuel lines from the tank (rust, flakes of paint etc). As you accelerate harder the debris gets forced forward and causes blockages and restricts the fuel. As you ease off the debris settles back and the slower fuel rate lets it run fine.
 
Thank you Dale

I have emptied the fuel tank recently and all seems clean fuel filter seems clean even had the float chamber lids off and checked the inlet valves on them. Also when I open the mixture nut it will run fine under load albeit very rich. So the fuel flow to the carbs is fine.
 
Sounds like a needle problem. Try "Burlen Carb Services", I'm pretty sure they will have dealt with Z's before. 01722 412500.
 
If you want to know what needles you have now it should be marked on the shoulder bit of the needle that fixes into the dashpot (the thing that goes up and down inside the carb).
 
Have you got any oil in the dash-pots - the area under the black screw caps on top of the carbs. Have you got a workshop manual
 
Nigel, thank you, just had a look at the website. I'll have a look at the number on the shoulder tomorrow.

Rob, yes I have been told by several people that 3 in 1 is a good sub for proper dash pot oil. Cheers

Mike, I was planing on giving you a bell tomorrow. Thank you.
 
That's a good question..... I have not had the car running properly on these needles, only got it to run/ drive by opening the jets a lot, but I have no clue if these are original or if the car ran with these needles.
 
What carbs/engine setup are you running?
It sounds very much the same as the problems I am having with my su hs8/l28 setup. Have been looking through old invoices that came with the car and I have a invoice for bbl needles which are off a 4.2l jag, so I am going to order bau needles which are from the 2.8l version and see if that makes any difference(unless someone has any better ideas).
 
I have a standard L24 with HJG46W's on so all standard. Cheers Leeski26
Its a pain because there seems to be no wear or any other problems that I can pinpoint.

Can anyone tell me what numbers I should see on the shoulder of my jet needle if it is standard? just so I know before I remove it tonight. (if there is such a thing as a standard needle!!)
 
There are no markings on my cars needles (so presume they are aftermarket). I do have an idling issue (basically the idle speed gradually reduces and without a throttle prompt will cut the engine within 45-60 seconds!). That said it runs ok and over 3000 rpm it goes like stink without any hesitation!! Haven't a clue why but can live with it.
 
So I have just returned from DJR as I'm lucky enough to live down the road from him. After chugging up to his with lots of chock we found one carb was fine but the little filter (I didn't even know there was one there) on the front float bowel was clogged but not enough to effect it at idle. Then we went for a spin and it cleared up nice and is running well. Learnt a lot from DJR and would like to thank you all for your help and Dale you got it.

So I will be seeing you at Castle Combe

Stockdale wish I could help. I do recall when I first got mine running after sitting for five years I had the same idle reducing but could never get it to run well at high revs either. Good luck.
 
I had the same issue a while back. A new tank, a few replacement sections of the line that were showing signs of corrosion, new filter and a good flush out fixed it. It's very satisfying when its revs freely past the point it was giving up at before. :D::driving:
 
Stockdale said:
There are no markings on my cars needles (so presume they are aftermarket). I do have an idling issue (basically the idle speed gradually reduces and without a throttle prompt will cut the engine within 45-60 seconds!). That said it runs ok and over 3000 rpm it goes like stink without any hesitation!! Haven't a clue why but can live with it.
Click to expand...

Is the float chamber slowly overfilling?
 
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