Author Topic: Bis 30DGF Float level?  (Read 321 times)

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elanman99

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Bis 30DGF Float level?
« on: July 22, 2018, 09:48:25 PM »
I am still struggling to get my 126 bis to run properly.

A few months ago I posted a question here (see http://club126uk.co.uk/forum/index.php?topic=11205.0) but in spite of the good advice I was given am unable to make sense of the problem.

I have spent the last hour searching the forum archives and cannot find a definitive measurement to set the float level for the 30DGF. Lots of mentions in posts of people saying they have set the level according to the manual. I have the manual (on CD from this site) and nowhere does it show how to set the float level although on the 'Technical Data' (page 24) it states 9.5 to 10.5 with gasket. The only measurement I found in the archives was 6 or 7mm and that is what it is set to now. Fuel no longer drips continuously onto the butterfly so the fuel level is probably not too high (and the float does not leak).

The only way I can get the engine to run is by using my hand to almost completely choke the engine, it dies instantly when its not choked. Opening the throttle momentarily speeds the engine but I think that is the extra fuel from the accelerator pump.

I dont want to give up on this but can anyone recommend a Fiat friendly garage in Cheshire/Lancashire?   


Ian
Located in Sunny Sandiway

Pete126

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Re: Bis 30DGF Float level?
« Reply #1 on: July 23, 2018, 01:18:04 AM »
Hi Ian, If as you say the engine will only run on full choke that would suggest that there is an air leak somewhere on the induction side, Have you connected all the Vacuum Hoses to the Carb and he Vacuum Relay, also if you spray carb cleaner round the base of the carb and the revs increase you need to reseal or replace the gasket

Pete.      il cavallo piccolo

elanman99

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Re: Bis 30DGF Float level?
« Reply #2 on: July 23, 2018, 10:00:12 PM »
I have just tried again after blanking off the ports that go to the solenoid. I left the pipe connected to the distributor as that seems to be leak free (I can see the CB mounting plate oscillating when the engine is drawing a vacuum). I had difficulty getting the engine to fire at all as no fuel seemed to be present. I did manage to start and run by dribbling petrol into the choke tube directly from an oil can but it would not run on the carburettor.

Before the engine ran there was nothing coming out of the accelerator pump jet (presumably the float chamber was empty), after a few minutes 'running', the accelerator pump shot out fuel as expected.

To eliminate the fuel pump (and possibly stale petrol) yesterday I rigged up a small temporary tank on the open tailgate so the carb was fed by gravity. The engine behavior was no different than with the normal tank and pump.
In my experiments a few weeks ago there was an excess of fuel continuously dripping into the choke tube, now that I have set the float level to 6mm I seem to have a lack of fuel.   

There seems very little published information on the 30DGF, I have stripped and cleaned this one several times and as far as I can tell assembled and adjusted it correctly (apart from the float level). There are two jets (about 30mm long) which have different holes and drilling patterns but I can find nothing to identify which one goes in which position.

I was going to buy the Haynes Weber manual but apparently it does not cover the 30DGF.

Please can anyone point me to a source of info on this carb?

Ian


 
Located in Sunny Sandiway

Pete126

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Re: Bis 30DGF Float level?
« Reply #3 on: July 23, 2018, 10:35:23 PM »
Hi Mate, reading through you seem to have covered the carb many times, when the engine started on full choke was it fireing on both cylinders?
Pete.      il cavallo piccolo

elanman99

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Re: Bis 30DGF Float level?
« Reply #4 on: July 23, 2018, 11:03:51 PM »
Yes runs quite sweetly (in the mechanical sense) on both cylinders.

Tomorrow I will take the carb off and double check the gasket to manifold joint. I made the gaskets and a 6mm insulating spacer plate as when I got the car the carb just had a paper gasket.

Ian
Located in Sunny Sandiway

Xylaquin

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Re: Bis 30DGF Float level?
« Reply #5 on: July 23, 2018, 11:16:04 PM »
Apart from the information in the workshop manual, I stumbled across this French tear-down:
http://www.pouleto.ch/fiat500/?p=332

Notably, it contains this diagram, but I've yet to find where it comes from originally (a guide perhaps?)