Technical Carb set-up

[Paul64]

Hi,
I have had my 1995 Cinque for 3 years now and really no problems at all!
I service it regularly but this time, I will need to re-set the idle speed as it's pretty low, especially when the fan cuts in. There is also some regular hunting at idle speed brought on by the diaphragm actuators...
The engine is the 700cc twin with an Aisan carburettor, covered in emission controls and adjustments.
Does anyone have a basic set up for this carb as I have had a little play but to no avail....

Any help would be most appreciated!!!

Paul

 

[Brooky]

700cc ,i dont know anybody with one so good luck getting info out of us.lol. You have any pictures of it??

 

[Alan.D]

Won't be a carb it will be SPI (they look the same) and being a Fiat SPI it will also have the motor at the botom of the SPI which controls the idle. They often gum up so give a clean out which should help.

Idle should be controlled by the ECU for a 1995, I assume the car has a cat.

 

[randomizered]

I'm sure cc1 had one, he maybe able to give a hand

They were never released over here though, and rare as anything!

Kristian

 

[arc]

Won't be a carb it will be SPI (they look the same) and being a Fiat SPI it will also have the motor at the botom of the SPI which controls the idle. They often gum up so give a clean out which should help.

Idle should be controlled by the ECU for a 1995, I assume the car has a cat.

iirc the 704cc engine uses an electronically controlled carb, not an SPI unit like whats found on the 903/899cc engines.

 

[cc1]

I had a weber carb on mine.(nice and simple). The asian carb has more diaphrams than a family planing clinic. One of the diaphrams could have split.

 

[Alan.D]

iirc the 704cc engine uses an electronically controlled carb, not an SPI unit like whats found on the 903/899cc engines.

At 1995 I expect it has a cat so has to be controlled, what's the difference between an electronically controlled SPI and electronically controlled carb?
Late 750's are SPI as well. I once did see a hybrid on the swiss version of the panda 4x4 had the old style dizzy with SPI

Genuine question I'm not trying to take the pi$$

 

[Paul64]

Hi Guys,

Thanks for the interest - it's certainly a PITA as it is at the moment...
I wonder if there is a conversion kit for the Weber at a reasonable price? There are certainly more bits and pieces hanging off the carb than an Xmas tree.
I guess it's pretty much the last step in induction before the SPI takes over but it must make a whole lot more problems for servicing.
I'll have a look at the Weber website and see what there is.

Paul

 

[arc]

At 1995 I expect it has a cat so has to be controlled, what's the difference between an electronically controlled SPI and electronically controlled carb?
Late 750's are SPI as well. I once did see a hybrid on the swiss version of the panda 4x4 had the old style dizzy with SPI

Genuine question I'm not trying to take the pi$$

i've never seen a 704cc, let alone worked on one and the information about them is tricky to find.. my guess would be that it has no fuel pump, and instead draws fuel through in the same way that a carb does. suspect the ignition system will be seperate from the fuel system, and so won't have the likes of TDC sensors.

Carbs are witchcraft to me, so i'm not sure what could be electronically controlled in one of them.

 

[rallycinq]

Undo Diaphragm adjustment screw so that the screw head comes into line with outer hub.

Adjust throttle opening screw so that engine speed is 950 rpm.

Check CO level is 1.0 - 1.5 Vol %.

Adjust with screw

Decrease idle speed slightly by exerting pressure on the screw. Maintain pressure and retighten so that engine spped is 30-50 rpm below specification.

Reseal diaphragm adjusting screw with silicone sealant.

Hope this helps

Cheers

D

 

[cc1]

The Asian carb is controlled by an ecu so changing to a weber is not a simple job. Best bet is to buy a complete throttle body.

 

[Paul64]

Thanks for the info! I had a play last night and it seems to be a lot better - it certainly makes you realise how easy injection systems are to run and maintain now....
There is an electric fuel pump in the tank - you can hear it for a second when the ignition is switched on before engaging the starter - that boosts pressure to the engine pump then the rest of the system basically a carb with lots of vacuum actuators and electric valves hanging off it.

I was wondering what would happen if I disconnected all the diaphragms and left if purely as a cable controlled throttle? That would be an ultimate cure-all I guess...??

Paul

 

[levemircento]

it would be great for us in the uk to see some pics of that set up, well, I could be speaking for myself but I know I'd liek to have a gander!!

 

[arc]

indeed, would love to see some photos of this setup and of the rest of the engine bay too.

 

[Ffoxy]

I had a weber carb on mine.(nice and simple). The asian carb has more diaphrams than a family planing clinic. One of the diaphrams could have split.

Pmsl at that!

 

[Paul64]

Hi,
I've been away for a few days, yes, in the Fiat! No probs and runs fine now.
I'll nip out and get a photo this afternoon and load it up... 30hp, 4 speed box, 140km/hr on the motorway, as long as it's very flat of course. 80 on the hills.

 

[Paul64]

Here we go....

Plugs accessed through the wheelarch liner as the engine lies at 90 degrees to vertical.
Famous carb covered in emission gear.

Great fun!

Paul

 

[levemircento]

great

whees the gearbox seeing as the engine is longitudinal

 

[cc1]

Mine had 31hp and did about 160kmh before hitting the rev limiter at 3300rpm.

 

[Paul64]

I think I could get it up to 31hp if I cut the cat out of it..... Had nearly 150 on a long flat with a little wind assistance a few months ago. As a basic run-around and occasional load-lugger, I've had no problems with it so far except aforementioned idle problem.... Well done Fiat!