So near yet so far! All ready to go, gone to get it MOT'd, and it is running weak +++. I have put a new fuel pump on as the original was performing poorly, but I have a terrible flat spot, and the engine will only run/accelerate with a little choke, except in top gear, it will barely run at all. I suspect the carb. Does anybody have a spare one hanging around I can have, or is there a more simple reason? Any help or ideas most welcome.
- Thread starter tim1casa
- Start date
Steve Hennessey
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All, this points to an air leak: manifold gasket, carb base gaskets, missing air screw in base of carb, split emission pipe (that goes to the inlet manifold). Test the gaskets by running the engine and squirting WD40 or similar along the join to see if it gets sucked in.
Leaky
That sounds very plausible. We had the head and manifold off, but the new gasket set didn't have the correct manifold gasket, so we used the original. I'll give the WD40 a go on Friday. Passed its MOT. The guy reckoned he could have eaten his lunch off the underneath if he'd turned it over. I'll put some photos on now it's finished, almost.
That sounds very plausible. We had the head and manifold off, but the new gasket set didn't have the correct manifold gasket, so we used the original. I'll give the WD40 a go on Friday. Passed its MOT. The guy reckoned he could have eaten his lunch off the underneath if he'd turned it over. I'll put some photos on now it's finished, almost.
Re-build
Glad you like it. An awful lot of effort mainly by a friend. The van body had been sorely beaten up, and as a result has quite a lot of filler in it, so it is not perfect. Tried to find an air leak today, but couldn't. Friend who has helped me do this up suspects main jet has the broken tip of the adjusting needle left in it. He says he's seen it before with cars and bykes. Someone screws it in tightly, and then it breaks off inside the jet, so I'm on the look out for another carb.
Glad you like it. An awful lot of effort mainly by a friend. The van body had been sorely beaten up, and as a result has quite a lot of filler in it, so it is not perfect. Tried to find an air leak today, but couldn't. Friend who has helped me do this up suspects main jet has the broken tip of the adjusting needle left in it. He says he's seen it before with cars and bykes. Someone screws it in tightly, and then it breaks off inside the jet, so I'm on the look out for another carb.
jjad
Enthusiast
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- Herefordshire
Do you need a whole new carb, or could you rebuild?
I just bought a rebuild kit from www.karengine.co.uk for the Zenith IF 28:
http://www.karengine.co.uk/Kes/BUYGUIDE/HTML/UCK83.HTM
I just bought a rebuild kit from www.karengine.co.uk for the Zenith IF 28:
http://www.karengine.co.uk/Kes/BUYGUIDE/HTML/UCK83.HTM
Carburettor
My friend thinks it's the needle valve tip stuck in the main jet or old fuel crystallized in the passages. Screwing the needle valve in or out made no difference whatsoever to the engine revs/flat spot. I have been in touch with a vendor on the French Ebay site, who has a fully reconditioned carb, but it's not going to be cheap. So I am hanging on in case somebody on this site has got a spare one to sell, or the Euro plunges into oblivion, without dragging the £ with it!
My friend thinks it's the needle valve tip stuck in the main jet or old fuel crystallized in the passages. Screwing the needle valve in or out made no difference whatsoever to the engine revs/flat spot. I have been in touch with a vendor on the French Ebay site, who has a fully reconditioned carb, but it's not going to be cheap. So I am hanging on in case somebody on this site has got a spare one to sell, or the Euro plunges into oblivion, without dragging the £ with it!
Cornish4
Le Dazzleur
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You've done a great job, and I love that colour, but then I am bias, it looks like Tournesol to me, same colour as our 4. Can you not strip the carb and remove the offending needle point and then replace the needle? Our car was running very weak at one time and I simply drilled out the main-jet to 1mm from .9mm, so this might help of you have a worn carb. Emissions are now spot on, and it still does 40mpg or thereabouts. Regards Brian.