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Float level issue, Zenith 32IF7 carb 845 engine 1985 R4 TL

Fentible

Enthusiast
Messages
20
Location
Gateshead
#1
I bought a carb repair kit from vehicules-anciens.fr, I was taking the carb off anyway to do some general cleaning and to replace the leaky gasket between it and the manifold.
Car ran reasonably well prior. New kit fitted, which included new plunger for the accelerator pump and a shiny new needle valve. I checked and adjusted the accelerator pump stroke and the gap between the flap and actuating rod when the choke was closed. There had previously been no gap between the two.
On startup it was apparent that the carb was flooding badly, rough idle, black smoke and a strong smell of petrol. Removed carb top and rechecked the needle valve, thinking I might have dislodged some dirt.
Blowing through the fuel inlet and pressing the plunger on the needle valve stopped the air, so that appeared to be working fine. All back together and exactly the same thing happened again, so I refitted the old needle valve, perfect start and tickover. Except now the car refused to rev cleanly. A quick jab of the accelerator caused the car to cut out and building the revs it was clear that the engine was not happy. I'm now thinking fuel starvation, so I did what I should have done prior and checked the fuel level.
The manual states, that you measure from the gasket face, without gasket, to the extended tip of the float needle with a range of 11.85 -12.05mm. Closest I can get is 13.5mm, nipping the valve tightly to the point I fear stripping the threads and fitting the thinnest washer I have. Which means the float isn't coming up as far as it should. If I remove the washer, I can just about hit 12.05mm but obviously with no sealing washer, there will be fuel leaking past the needle valve body.
What I find odd is that the car was revving fine with this needle valve and original washer. I will compare the old and new gasket as I have a feeling the new one is thinner. Has anyone else come up with this problem?
 
Messages
973
Location
Cheltenham
#2
Just a thought - did you turn the top part of the carburettor upside down before measuring? I only ask because you say 'to the extended tip of the float needle', which made me wonder if you had.
 

Fentible

Enthusiast
Messages
20
Location
Gateshead
#3
Hi Andy, no I measured it right way up....ie as fitted with the float needle pointing down so it was extended. I'm heading out to the car now so I can compare gaskets and whip out the main jet to see if anything else is lodged.
 
Messages
973
Location
Cheltenham
#4
I think that may well be the problem (or at least part of it) - the measurement is supposed to be taken with the needle valve pointing skywards - a couple of quotes from R5 manuals re the 32IF7:

'Remove upper part of carburettor body, detach gasket from flange. Holding upper part of carburettor body, upside down and horizontal, measure distance between body flange and needle valve tip'

And from the RTA:
'- Déposer le couvercle du carburateur et enlever le joint d'étanchéité.
- Retourner le couvercle et mesurer la cote comprise entre la partie la plus haute de la bille du pointeau et le plan de joint...'
 

Fentible

Enthusiast
Messages
20
Location
Gateshead
#5
Hi Andy, that makes things confusing. But its not unknown for Haynes to be wrong on occasion. In any event, I removed the washer from under the float valve and wound plumbers tape around the threads. Measurement with the float valve pointing down is exactly 12mm. The old (original?) gasket was slightly thicker but my car now starts, idles and revs cleanly with the exception of transition from choke to off choke where the engine will falter when I try to pick up the revs.....its almost like the car has to clear its throat but once cleared, ticks over and revs cleanly. In fairness it was doing that before I removed the carb and its not noticeable under normal driving conditions.
 
Messages
973
Location
Cheltenham
#6
It's true that there are sometimes inaccuracies and ambiguities in the various manuals - but they all talk about measuring float/fuel level with the top of the carburettor inverted (there's a diagram of an inverted Zenith 28IF top in the part of the later Haynes manuals that deals with Cléon engines). In the text it says 'With the needle valve ball in the extended position, check the fuel level.....is as specified'. I remember being confused by this until I realised that it meant that the tiny ball bearing shouldn't be pushed in when the measurement is being taken.
I'm not sure how well the tape will withstand E5!
Anyway, good luck!
 
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