Sticky situation, stuck second butterfly on the carburetor.

[Chromaphase]

hi Everyone,
I recently acquiered my very first X1/9 (1500cc, 1985, Europe)
But I have what we could literally call a "sticky" situation.

I was driving and the acceleration pedal was stuck to the floor, dangerous indeed !

we shot a video of the problem here : VIDEO

First, I was thinking its a pedal problem, but actually it's coming from the carburetor (34 DATR) that have been redone by the previous ownor.
What is happening is this, as the second butterfly lever is moving, at half way it stays stuck in place. I tried break cleaner, and also to add grease, to no effect at all.
Is this a common problem on this carb and is there any way to fix it ?

and to fully open the second butterfly at 100%, I really need to push a lot as well.

Also the accelerator pedal wasnt feeling great anyway, it's because I guess the sticky second butterfly added too much effort on the wire.
as you can see on the second photo, the cable needs to be retighten, however I have no idea how to do it properly is someone can guide me on this secondary problem it would be great. I can see there is a nut but nothing to hold the whole thing to grab that nut and turn it to begin with.

I would say I wasn't impressed at all when I first tested the car by it's power. But indeed when I was pressing the pedal to the floor, maybe it would go only to 25% of the second butterfly...

Thanks for your insights,

Matthieu

 

[JimD]

Check the cable itself to be sure it isn't sticking inside the sheath. If a strand of the wire unravels, it can cause the cable to bind.

 

[twincam69]

Disconnect the throttle cable before you go too far and check the operation at the carb.

 

[Chromaphase]

Check the cable itself to be sure it isn't sticking inside the sheath. If a strand of the wire unravels, it can cause the cable to bind.

I checked it first but it wasnt coming from there.

Disconnect the throttle cable before you go too far and check the operation at the carb.

yes it's what I have done so far, to try to isolate the problem. As you can see in the video we are operating the carb by itself but the second butterfly is very sticky...

 

[twincam69]

Throttle shaft bent?

 

[carl]

Take the carb off the manifold, flip it over and spray WD40 or a similar spray lubricant onto the throttle plate where the throttle spindle goes into the carb body and see if that loosens things up. Grease can't flow into any areas where the throttle spindle goes into the carb body.

 

[Chromaphase]

Throttle shaft bent?

You mean the one on top of the motor ? I just checked it's working fine.
But yeah, seems the only problem would be the throttle shaft inside the carb ?

I have another cab given by the seller of this car. on that one, its also not smooth in the throttle opening.
here in video : Video of the second carb I have

And on the carb on my X, it seems the second barrel shaft has a problem, but the first one seems to be sticky as well (but way less than the second, so I barely noticed before)

This Carb on my car has been "redone" 300km ago by a "professional" so I don't know what could have happened as the seller seems to drive very slowly actually.

Seems the only solution is to take off the entire carb ? But if I dont have other shafts to replace the bad ones, what should I do ? I mean these sticky throttle problem can be very dangerous on the road !

Thanks.

 

[fiatfactory]

The problem appears to be with the primary in both cases.

In the first video, when the throttle is opened 100%, the primary throttle shaft moves in an arc (i.e. doesn't pivot around it's centre point) at the extreme end of movement, this indicates the bushing inside is either missing or worn out. There is a thin nylon sleeve and a nylon seal tucked in there on the lever side, on the pump cam side there is a disc valve for crankcase vapour recirculation, so the spindle bush being worn (badly) or missing (possible if the carb has been dipped to clean it) , when the shaft moves off centre it can stick against the carb body

The primary also has a nut/locktab on each side, so it's possible to overtighten these (both or just one) and it tends to pull the whole throttle shaft a little one way, which is possible problem number two.

Seeing as you have a spare off the car, pull it apart and have a look if loosening the locknuts on the primary shaft loosen it up.

SteveC

 

[Chromaphase]

The problem appears to be with the primary in both cases.

In the first video, when the throttle is opened 100%, the primary throttle shaft moves in an arc (i.e. doesn't pivot around it's centre point) at the extreme end of movement, this indicates the bushing inside is either missing or worn out. There is a thin nylon sleeve and a nylon seal tucked in there on the lever side, on the pump cam side there is a disc valve for crankcase vapour recirculation, so the spindle bush being worn (badly) or missing (possible if the carb has been dipped to clean it) , when the shaft moves off centre it can stick against the carb body

The primary also has a nut/locktab on each side, so it's possible to overtighten these (both or just one) and it tends to pull the whole throttle shaft a little one way, which is possible problem number two.

Seeing as you have a spare off the car, pull it apart and have a look if loosening the locknuts on the primary shaft loosen it up.

SteveC

Hi Steve, thanks for the feedbacks, Im going to have a look at the spare carb, and check all the part from the primary shaft. it's really werid that I have two carb and both seems to have the same problem, kind of concerning !

By the way, would you know how to adjust the throttle wire on the second pic of my first post ? At lest I couled drive the X around using just one barrel waitin to fix this issue.

 

[Chromaphase]

Take the carb off the manifold, flip it over and spray WD40 or a similar spray lubricant onto the throttle plate where the throttle spindle goes into the carb body and see if that loosens things up. Grease can't flow into any areas where the throttle spindle goes into the carb body.

The problem appears to be with the primary in both cases.

In the first video, when the throttle is opened 100%, the primary throttle shaft moves in an arc (i.e. doesn't pivot around it's centre point) at the extreme end of movement, this indicates the bushing inside is either missing or worn out. There is a thin nylon sleeve and a nylon seal tucked in there on the lever side, on the pump cam side there is a disc valve for crankcase vapour recirculation, so the spindle bush being worn (badly) or missing (possible if the carb has been dipped to clean it) , when the shaft moves off centre it can stick against the carb body

The primary also has a nut/locktab on each side, so it's possible to overtighten these (both or just one) and it tends to pull the whole throttle shaft a little one way, which is possible problem number two.

Seeing as you have a spare off the car, pull it apart and have a look if loosening the locknuts on the primary shaft loosen it up.

SteveC

Actually I tested WD40 on the spare Carb I got that was sticky and... it's working great now.

However I tried to spray WD 40 on the one in the car but no improvement. I'm little worried as to spray the WD 40 right down the barrel of the carb on my Car. It's classic WD 40... what do you think ? Other sprays I got are Brake Cleaner and a wd equivalent from Bardohl. I dón't want to do a terrible mistake on it !

If this doesn't work then I need to take the Carburetor apart as recommanded by fiatfactory but it's gonna be tricky as I had never done it, nor I have a cleaning kit for this carb, gaskets etc...

 

[fiatfactory]

Hold the cable at the part being pointed to by the red arrow, from memory a 5mm open ender or a small adjustable will grip here

Loosen the locking nut shown by the green arrow , from memory this is a 8mm spanner size

Remove the clip holding the cable end shown at the blue arrow (removed already in the picture) and wind the end on/ off to shorten / lengthen , tighten / loosen the cable

dont try adjust it while the ball / socket are connected, or it tends to unspiral the cable
SteveC

 

[carl]

As pointed out by Steve, it does look in the first video that the throttle shaft moves radially which it shouldn't. Also, to truly test the carb on the car you need to undo the long rod from the carb to eliminate any possibility that the linkage is the problem rather than the carb parts. WD40 can be swallowed by the engine with no problem. I recommended it to lubricate and clean the throttle shaft as it passes through the carb body, brake cleaner won't lube anything, just a cleaner. I have had throttle shaft end nuts that were too tight and would bind up the motion of the primary throttle shaft but if your primary throttle works smoothly then this would suggest the nut is not too tight.

The carb motion will get harder as the secondary is engaged but the movement should be smooth and definitely snap back when you get off the gas pedal.

Beware of experts, enthusiasts, top mechanics and other self described folk who work on cars or carbs.

 

[Chromaphase]

Hold the cable at the part being pointed to by the red arrow, from memory a 5mm open ender or a small adjustable will grip here

Loosen the locking nut shown by the green arrow , from memory this is a 8mm spanner size

Remove the clip holding the cable end shown at the blue arrow (removed already in the picture) and wind the end on/ off to shorten / lengthen , tighten / loosen the cable

View attachment 72926
dont try adjust it while the ball / socket are connected, or it tends to unspiral the cable
SteveC

Thanks ! It's very clear now ! However even using wd40 on it and trying my best, it is very stuck... I don't know what to do to loosen it...

 

[Chromaphase]

As pointed out by Steve, it does look in the first video that the throttle shaft moves radially which it shouldn't. Also, to truly test the carb on the car you need to undo the long rod from the carb to eliminate any possibility that the linkage is the problem rather than the carb parts. WD40 can be swallowed by the engine with no problem. I recommended it to lubricate and clean the throttle shaft as it passes through the carb body, brake cleaner won't lube anything, just a cleaner. I have had throttle shaft end nuts that were too tight and would bind up the motion of the primary throttle shaft but if your primary throttle works smoothly then this would suggest the nut is not too tight.

The carb motion will get harder as the secondary is engaged but the movement should be smooth and definitely snap back when you get off the gas pedal.

Beware of experts, enthusiasts, top mechanics and other self described folk who work on cars or carbs.

So the spare Carb is working great now after the wd40 on it.

I did untight a bit the nut on the main shaft, and it seems to move more freely now ! So I think it was a bit too tight on this part. Also Now Im really sure it's the second shaft that is the problem because after unscrewing the nut from the primary, I can really move the primary freely all the way to open and back.

For now, the secondary will stay stuck after maybe 50% open. Sprayed WD40 into the secondary barrel, no change unfortunatly.

The secondary only have one nut on the other side, i did unthight it as well but no change. On the spare carb there is a little bit of play in the secondary shaft when it is opening, and the play stay even at full open. However on the main carb, the play is very little and absolutly no play in the shaft when the butterfly is more than 50% open.

Which would indicate corrosion or bent secondary shaft that block it after 50% open ?

I guess I'm running out of option to fix this, beside taking this carb out and switch the secondary shaft with the secondary of the spare carb I have. But I'm not sure I could perform such work.

 

[fiatfactory]

It could be something as simple as the wrong phenolic spacer under the carb... I've seen 34's mounted on spacers made for a 32 and the butterfly would jam against the sides of the (slightly too small) 32mm hole...

First course of action would be to remove the carb from the manifold and take a look

Secondary throttle shaft is highly unlikely to be bent / twisted... more probable is the throttle butterfly disc may not be properly centred... if it's been apart and rebuilt maybe someone removed the discs and didn't get them set right

SteveC

 

[Chromaphase]

It could be something as simple as the wrong phenolic spacer under the carb... I've seen 34's mounted on spacers made for a 32 and the butterfly would jam against the sides of the (slightly too small) 32mm hole...

First course of action would be to remove the carb from the manifold and take a look

Secondary throttle shaft is highly unlikely to be bent / twisted... more probable is the throttle butterfly disc may not be properly centred... if it's been apart and rebuilt maybe someone removed the discs and didn't get them set right

SteveC

I see... yes It would make sens that it wouldn't be bent, I agree with you. If I remove the carb, do I need to change the gasket even if it gasket in place didnt do much time? I think the guy taht sold it to me was driving it way too slow (keep telling me, take care of this car, dont push it too much...) but actually I can see that he never went full throttle using the car and maybe never realized that garage that worked on the carb got it very wrong !

I was very underwlemed by the car performance when I took it for a little ride after i bought it, kind of glad to know it was just 50% of the throttle !!

 

[carl]

Again, I agree with Steve that the secondary throttle plate might be hitting and binding on the phenolic spacer below it, I have seen this several times. Very simple to remove the carb, just remove the four nuts/lockwashers holding it down on the manifold. You won't be sure of what the problem is till you remove it.

 

[Chromaphase]

Again, I agree with Steve that the secondary throttle plate might be hitting and binding on the phenolic spacer below it, I have seen this several times. Very simple to remove the carb, just remove the four nuts/lockwashers holding it down on the manifold. You won't be sure of what the problem is till you remove it.

Ok thanks, I will do this ! One last question, do I need absolutly to change the gasket if I'm removing the carb ?

 

[kmead]

Ok thanks, I will do this ! One last question, do I need absolutly to change the gasket if I'm removing the carb ?

No but you might consider using a product like Formagasket which doesn’t dry out. It really depends on what what was done in the past and how the part looks when you take things apart (plus your care in taking it apart… )

 

[carl]

I have removed and reinstalled carbs many times without replacing the gasket. It's a matter of looking at the gasket and making sure it's not torn or worn out. A simple test when everything is back together and the car is idling is to shoot WD40 where the carb meets the phenolic spacer and see if the idle speed changes, indicating a possible vacuum leak.