New to Zenith - Running Lumpy ?

Technical questions and Maintenance advice post in here please
Nikki&Austin
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Re: New to Zenith - Running Lumpy ?

Post by Nikki&Austin »

does anyone have a photo of where the fuel line goes into an installed HS2, ordering manifold and carb today, not sure whether the furl line run from pump to carb is similar or fundamentally different
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Neil Evans
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Re: New to Zenith - Running Lumpy ?

Post by Neil Evans »

The pump to carb pipe is straightforward enough. the SU equipped cars just have a short length of rubber pipe to connect it at the carburettor end...
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Re: New to Zenith - Running Lumpy ?

Post by Paulc »

Like this. Obviously since this photo was taken the engine bay has been extensively cleaned and refurbished :whistle:
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Nikki&Austin
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Re: New to Zenith - Running Lumpy ?

Post by Nikki&Austin »

Thanks Paul, but sorry, I can't see the carb under all that dust !!! :thumbs: as soon as we posted, I remembered that as with the TR, it was a case of just connecting with some flexibleline - so the £5.95 sealey fuel amazon pipe bender might not get to be used just yet - but we do have some fancy braided fuel line left over from the TR and some dandy red fuel line finishers!

Back to serious Q's, for the vacuum advance, presumably again just replace that stiff ally tube with some flexible hose ?

Apologies for some dumb Q's, but on a fast learning curve and advice gratefully received.
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Re: New to Zenith - Running Lumpy ?

Post by Edosan »

For vacuum advance you just need a small piece of appropriate size tubing to connect the end of the existing pipe to the port on the carb. if you have a newer distributor with push type fitting you can replace the whole metal pipe with a flexible plastic pipe which are widely available and used on later A series engines.
For fuel connection I would strongly recommend purchasing some new flexible hose which is specifically for modern unleaded fuels. Older materials can perish more quickly with modern fuels and braided hoses can simply hide the deterioration in the rubber. :wave:
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Re: New to Zenith - Running Lumpy ?

Post by Bill »

Edosan wrote:For vacuum advance you just need a small piece of appropriate size tubing to connect the end of the existing pipe to the port on the carb. if you have a newer distributor with push type fitting you can replace the whole metal pipe with a flexible plastic pipe which are widely available and used on later A series engines.
For fuel connection I would strongly recommend purchasing some new flexible hose which is specifically for modern unleaded fuels. Older materials can perish more quickly with modern fuels and braided hoses can simply hide the deterioration in the rubber. :wave:
You can get everything you need from Burlin. I did and it was a breeze.
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Hoppend
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Re: New to Zenith - Running Lumpy ?

Post by Hoppend »

Question: has anybody had the problem with an SU carb that pushed fuel thrue the vacuum advance tube? Am I correct that MM's are fitted with a fuel trap? Would love to here what can cause this.
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A40FARINAGURU
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Re: New to Zenith - Running Lumpy ?

Post by A40FARINAGURU »

Hoppend wrote:Question: has anybody had the problem with an SU carb that pushed fuel through the vacuum advance tube? Am I correct that MM's are fitted with a fuel trap? Would love to here what can cause this.
yes they are & so are the A40 Farina with the SU, it was a metal pipe with the unit fitted part way through, Later vehicles like Mini's Allegro's Marina's etc did not have them & it was just a plastic tube
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Neil Evans
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Re: New to Zenith - Running Lumpy ?

Post by Neil Evans »

All A30 - A35's with a Zenith carb originally had a trap in the vacuum pipe... :thumbs:
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Nikki&Austin
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Re: New to Zenith - Running Lumpy ?

Post by Nikki&Austin »

fortunately we have a trap in the vacuum pipe, but sadly it isnt helping us - no car to use over the easter weekend grrrrrrr

the lumpiness has increased to a non-running ??

took the carb off again yesterday, check everything, made sure the FC and body/lid were all square, fitted new gaskets etc (set 2 of 3)

it still doesn't like starting - fires up and stops immediately

checked for leaks around manifold and nothing

at best this morning we got it to idle - no more

we can raise revs with choke , but even the slightest touch on the throttle and it stalls

we wondered if this meant the idle /slow jet was fine, but the main compensating jets were not?

they were cleaned out and new washers installed to the jests and plugs

before I use service kit No.3, any suggestions and what to target ?

(Top Gear like,the threat of the shiney new HS2 looms in the corner - but want to be clear this is a carb issue first and not something more fundamental ?)

fuel flow is still good.

ps - apart from a microscopic size difference, how do you tell the difference between a compensating jet washer and a main jet washer ?)

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A40FARINAGURU
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Re: New to Zenith - Running Lumpy ?

Post by A40FARINAGURU »

maybe you have a blocked jet, have you had them all out & checked them..
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Nelly
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Re: New to Zenith - Running Lumpy ?

Post by Nelly »

Have you checked the fuel pump's internal gauze filter?
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Nikki&Austin
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Re: New to Zenith - Running Lumpy ?

Post by Nikki&Austin »

Hi, yes, checked the fuel pump, filter not clogged, the PO's homemade gasket had deteriorated so I removed that (and made a new rubber top seal gasket), but having rebuilt the carb several times, there were no signs of any of it getting through to the jets - I will check the fuel line between pump and carb this morning.

The fuel pump seems to be a complete botch by the PO, he seems to have made a homemade diaphram - despite the fact that the whole assembly costs bugger all.

Unable to post pic as Photobucket seems to have gone down on all platforms !

Would a knackered pump explain the issue, i.e., it will (50% of the time start and idle for a bout a minute), revs rise slightly with choke, but not much, but as soon at you touch the throttle it dies, so I wonder whether a failing pump is unable to respond to the demand when the throttle is applied ?
Nikki&Austin
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Re: New to Zenith - Running Lumpy ?

Post by Nikki&Austin »

Paulc
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Re: New to Zenith - Running Lumpy ?

Post by Paulc »

Have you tried taking the plugs out, and with the ignition turned off, press the starter using the solenoid/starter switch. With the fuel pipe disconnected from the carb (and with a suitable receptacle for the petrol) you should get a steady spurt of fuel. Also, have you tested the needle valve? I think it was Neil who said 'most fuel problems are on the ignition side'!
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