General Poor Idle/fuel mixture

[Nacho]

Hi all,
I have a question on adusting the carburator on the 750 panda. It is a 1988 and has the one barrel Carter carburator. I have looked at it for an idle adjustment screw, but I can not find one. I have never seen a carburator look like this one. I also can not locate the mixture adjustment on it either. There should be a screw some place to adust the mixture. If any one has any info I would appreciate it. The engine is not a fire, so I believe.
Nacho

 

[John H]

I am not familiar with that carburettor, but..

You will probably find the mixture adjustment is under a plastic plug, or seal.

In some countries it is an offence to remove this "anti-tamper" plug.

I presume you've already given it a nice clean air filter - mucky old filters give rich mixture....


Regards


John H

 

[Nacho]

John H,
I have replaced the air filter, sparkplugs, dis cap, rotor, and plug wires. I thought this would cure the poor idle of the car, but it didnt help that much. Also the car need the choke on for most of the time I am running it. If the carburator was working correctly, the choke should only be needed to get the motor warm then take the choke off. Not this car, you have to keep it on almost for 5km of driving or the thing will shut off on me. I will look again at it to see if there is a little plug on it.
Nacho

 

[John H]

OK.

It's sometimes worth posting the obvious, as there is a wide variety of skills and experience between some FORUM members.

There is a possibility that your carburettor has worn out the butterfly valve spindle, which can cause a big air leak: giving you a very lean mixture - hence needing the choke longer than it aught to.
( I have read somewhere* the Weber is prone to this problem...If the FIRE engine suffers from fast idle, very weak mixture the reason is Weber carbs designed in Germany. These suffer from air leaks, hence fast idle and weak mixture. Fitting repair kit risky! Best by new from FIAT (£110 + VAT). Weber charges a lot more.)

Another consideration is that the coolant thermostat isn't working properly (always open a bit), and the engine doesn't warm up as quickly as it should, which will not help.
UK specification Pandas all have temperature gauges, so it's easy to know how quickly it warms up...

Finally(?) there is a warm air diverter valve in the air intake box which takes hot air off the exhaust manifold (via a bit a corrugated alloy tubing on the FIRE engined versions).
This valve sometimes stops working.
The alloy tubing can get left off when changing the air filter.

AFAIK, none of the latter usually causes much grief (in the UK), apart from carburettor icing when the air temperature is around freezing, but it all helps get warm air into the carburettor quickly, regardless of season.


Regards

John H


*
http://www.honestjohn.co.uk/index.php?url=/carbycar/index.htm

 

[Nacho]

Hi everyone,
I have good news on the problem. I was looking at the car yesterday and I finally found the mixture adjustment. The only thing was it was turned all the way tight. I could only adjust it a little, but the car runs ten times as good as it did before. The screw should have more adjustment then it does but I think it was tightened up to much and something is broken. I am letting it alone because it is good enough. If anyone is wondering where it is. I have the 750 non-fire. If you look at the left side of the carb by the throttle linkage there will be a big brass colored screw about in the middle of the carb from both left/right, and up/down. Thanks for the help.
Nacho