Citroen GS shenanigans

[mrcitroen]

My GS is in need of some carb adjustments. It was running a wee bit rough so I changed plugs & H.T leads. Runs a bit better, but I still think it is rough. The idle speed was way too high so I brought the speed down using the throttle stop screw. Item no 1 on the photo below is apparently the. Idle speed screw, but this does not seem to do much apart to give an air leak sound the more you screw it out. If this is the idle speed screw, how should the throttle stop be set as this obviously influences idle speed.

 

[Asimo]

The idle speed screw controls idle air which takes a different route, ie not past the throttle butterfly. If this adjustment doesn't work it probably means the idle jet is blocked. The throttle stop screw shouldn't be used to set idle speed, but of course it often is.

[mrcitroen]

Thanks.

 

Car is currently idling at around 1000rpm. What is the correct way to set throttle stop? I think I need. To go back to base and reset the carb.

 

The inlet filter blocked on the carb. I cleaned it but I think I should get a new one. Can't find any reference to parts for this carb on line. I have a Haynes carb manual, but is not in that. Pic is from the Haynes manual for the car, but does not give jet locations or rebuild info.

[Asimo]

Haynes says " don't adjust Solex throttle stops, factory set" , there is a lot of carb. info in the 1971 to 1979 GS manual I have, have you got the same Haynes or a later less useful one? I could scan stuff you dont have of your Haynes isn't the same ( no 290)

 

I have not touched one of these things for years ( a Solex carb) but I would try and get the stop screws back to where they were, use the dirt on the screw thread as a guide and then I would strip it and clean it, carefull with the gaskets and they should re-use. Blow out the jets, dont push pins or bits of wire into them! Fit new filter and follow the idle speed adjustment bit in the Haynes.

 

These things are very prone to bunging jets up with the gunk that comes out of the engine breather.

 

Carb. problems must be easy compared with other GS problems for sure!

[Six-cylinder]

How about doing a compression test across the four cylinders just to check all is ok?

[mrcitroen]

That is the same manual as I have. Gives plenty of info on what all the screws etc do, but no details on strip down & rebuild like the Haynes carb manual does(but not this model) might have a read through it as It might give a hint on how to set up throttle stop.

 

I think the carb needs a clean. The car was sitting for years then used intermittently and going by the state of the internal filter (I could not blow through it until cleaned) it may have some crud inside. I cannot find any rebuild kits online. Anyone know sources of carb bits?

[mrcitroen]

How about doing a compression test across the four cylinders just to check all is ok?

That is a good point and I may investigate.

[HillmanImp]

Need carb expert? Go on bike forum.

[Station]

Don't adjust the fuel/air mixture screw - if you do, screw it all the way in and count the amount of turns to make sure you know the default factory setting. Carbs do get cruddy. Spray water or carb cleaner to see if the idle changes to check for air leaks at the gaskets or vacuum pipes. Good luck, I hate carbs.

[Junkman]

I love carbs. They are the intelligent way of administering fuel to an engine.

 

However, is yours the model with an electric solenoid on the carb and does it have a voltage regulator outside the alternator?

[steve_earwig]

Nothing wrong with carbs, until they wear...

 

http://www.ebay.com/itm/KIT-REVISIONE-CARBURATORE-SOLEX-28-CIC-4-CITROEN-GS-PALLAS-/230899144491seems a bit pricey but that's pretty much the first thing that came up on Google so there's probably more out there...

 

There's probably no point in trying to adjust it until you know the inside isn't bunged up with cludge.

 

I suspect (not having touch one that I can recall) the function of the carb is the idle air sets the idle speed while the throttle is supposed to wind up until it's got no play but not to wind up it enough to increase idle.

 

Before you start fiddling with it I'd make a note of where everything is, wind screws in until resistance is felt and count the turns (don't try to wind them in hard as you can distort the seats and then nothing0s ever going to be right)

[garethj]

While the car is running, spray some carb cleaner around the outside of the carb.  If the revs rise there's an air leak and you can look more carefully in that area when you take it apart.

 

No need to go mad spraying the stuff or there'll be so much in the atmosphere some cleaner will get sucked in through the inlet and the revs will rise anyway.

 

The Solex carbs on old VWs could sometimes leak around the throttle spindle, just something else to look for.

[mrcitroen]

Cheers guys. Done a bit more googling last night and found a PDF Citroen tech bulletin in German about setting up the carb including how much the throttle should be held open by the stop.

 

It is indeed the one with a stop solenoid. I'm sure the alternator has a external reg. I have only had the car just over a month, so still finding my feet.

[garethj]

Is the stop solenoid just the thing that shuts off the fuel when you turn off the ignition to stop it running on?  With the ignition on, pull the spade connector off and touch it back on the terminal again, you should hear it click.

[mrcitroen]

Yes it clicks & pulling it off stops the engine.

[castros_bro]

If it were a bike's single carb and assuming there are no other issues,   start engine and let it get warm and all choke type things are off---turn the throttle stop screw (1 in your diag)  for "fast" tick over----- adjust the air bleed (3 in your diag) till the engine runs maximum speed so turning either way the speed drops off (this is setting the air/fuel ratio for tickover)---set the throttle stop screw (1 in your diag)  for the tickover you require.

[Sigmund Fraud]

If it were a bike's single carb and assuming there are no other issues,   start engine and let it get warm and all choke type things are off---turn the throttle stop screw (1 in your diag)  for "fast" tick over----- adjust the air bleed (3 in your diag) till the engine runs maximum speed so turning either way the speed drops off (this is setting the air/fuel ratio for tickover)---set the throttle stop screw (1 in your diag)  for the tickover you require.

 

^ WHS. It's what I've always done for carbs, never had any issues. Just make sure the ignition side is OK before fiddling with the carb, as this is what usually causes running problems.

 

Solexes (as most carbs) are remarkably simple. It shouldn't take more than an hour to take it off the manifold, remove the top and give the float chamber and jets a quick clean.

[Junkman]

It is indeed the one with a stop solenoid. I'm sure the alternator has a external reg. I have only had the car just over a month, so still finding my feet.

 

Is the idle erratic and does it stall sometimes without apparent reason, and can be restarted right away?

Does it not really react to any adjustments you try?

Is the battery voltage relatively high, and does it tend to boil the battery on longer trips?

[mrcitroen]

Okey dokey. I took the top cover off the carb and cleaned out the float chambers. There was a bit of brown slime / grunge at the bottom. Unscrewed the 2 long jets and generally gave every opening I could see a good blast with carb cleaner.

 

Result is that the proper idle speed screw now seems to work properly. Got a better idle, but still wavers a wee bit. When I get more time I will remove the whole lot & stick it in the ultrasonic cleaner.

 

I think I may have a weak fuel pump. I fitted an in line filter between the pump and carb to try and catch some of the crap I think may be in the system. The pump does not fill the filter. The BX has a similar arrangement and does. Could the extra resistance in the line be too much for the pump?

[mrcitroen]

Is the idle erratic and does it stall sometimes without apparent reason, and can be restarted right away?

Does it not really react to any adjustments you try?

Is the battery voltage relatively high, and does it tend to boil the battery on longer trips?

Not measured voltage. Not sure if it is overcharging. I have not done any more than a few wee test runs.

[Asimo]

I have not done any more than a few wee test runs.

Needs an Italian tune up!

[Sigmund Fraud]

I think I may have a weak fuel pump. I fitted an in line filter between the pump and carb to try and catch some of the crap I think may be in the system. The pump does not fill the filter. The BX has a similar arrangement and does. Could the extra resistance in the line be too much for the pump?

 

It doesn't really need to fill the filter, TBH. As long as there is enough flow to keep the float chamber full, you're OK.

 

If the flow is not enough, you will soon find out (when the thing cuts out and needs plenty of cranking to restart).

[mrcitroen]

Cheers guys. It is definitely running smoother, but with it being a bit on the chilly side & no muff (oo er missus) I'm not sure if it is fully warming up.

 

All good fun.

[dollywobbler]

Does sound like it needs a good run out, with muff. If they're anything like 2CVs, plugs and HT leads need to be decent too.

[mrcitroen]

Did not come with a muff. I have fitted new NGK plugs and Bougicord leads. Does need a good run, but it's on SORN so I'm being cautious.

[Asimo]

Photo's please.

 

I am a GS fan, although I have never been #### enough to own one.

 

Bon chance!

[mrcitroen]

Here you go. Not. The best . Taken at the P.O's residence.

 

 

 

 

[Mr_Bo11ox]

Good heavens, what a stunner!!!!!! WOULD WOULD WOULD

[dollywobbler]

Delicious.

[Six-cylinder]

If only mind looked like that.....