International Lancia Forums

After rebuilding my s3 1.3s fulvia's engine and having problems with a missfire (before and after rebuild) i found that it was a carb problem.

last night i removed both the carbs and proceeded with stripping them completely. taking care NOT to mix up screws or jets.

I have one question tho.

I was looking down the hole where the idle mixture screw is.

And i can clearly see that the front carb (closest to the radiator) has much smaller holes than the rear carb?

Is this a sign that carbs comes from different cars / someone messed with them.

Well their was a bit of gunky stuff at the bottom where the accelerator pump and everytime i flooded the floats with carb cleaner the car ran fine for a while and then no 3 started a little misfire again.

I hope this cleaning solves my problem.

I was just curious about the different sized holes?

any info would be appreciated

Thank you

Heinrich (south africa)

Another question

I'm still looking in the forum if there isn't written about it somewhere.

But how to i set the floats or check that mine is correct.

I have some fulvia documentation and they talk about a tool.

does someone have measurements?

Thanks

Heinrich

Hi

funny enough those two holes where the same size ,the one carb was just dirty.

After putting carbs through chemical bath and carefully assembling and putting back on car, my idling is SUPER smooth , i put them back on over the weekend. I got balance correct ,and then the idle mixtures.

The car REALLY goes great now, And i don't even need to use the choke, when cold it idles smoothely at about 400rpm and as it gets hot goes up to about 700rpm.

another question.
I had to screw out each of the idle mixture screws about 3.5 full turns before the idle got stready, is this normal , or way out?

Thanks ,heinrich

The various 35PHH versions are all different. Some need about half a turn, some much more. If the car idles nicely and the setting is about the same for all 4 I would not worry too much.

On most it does make a difference in CO output if you arrive at the optimum by screwing the mixture screw in or screwing it out. You need the setting achieved by screwing the mixture screw out. See 3 below

What I do is:
1. find the optimimum settings

2. screw the mixture screws in till the stop (careful) one by one. The drop in rpm should be the same for all four . If there is a difference between carb 1 and carb 2 you can play with the balance screw

3. with the screws still at optimum screw them in one by one about a turn and unscrew till it reaches the point where the engine runs smoothly again and leave it there. This is usually a fraction of a turn below the setting achieved by just going for maximum rpm on all of them. It results in a CO output of 4,5%. If I just go for maximum I arrive at 7% most of the time, which is too much.

If there is so much wear on butterflies, barrels and shafts that the engine does not stall with the idle screw fully retracted you can set the balance for minimum rpm. Then adjust the mixture screws as above. Repeat it a hundred times or as many as necessary to achieve a stable result. This only works if the idle screw does not touch the lever. Then check if 2 above improves things. You only need to try this once. If you know how your carbs on your engine behave you can optimise your procedure. Then go for 3 above.

I was just SO happy to see my no.3 misfire going away after refitting them

When i had the carb off i checked the shafts for play.

When the trottles /butterflies where closed i could not feel any play, When FULLY open there was a bit of end to end play, but luckily no play in the shaft bushes , there are no air leaks in those bushes.

before the carb clean i could screw those mixture screws full turns with VERY little change , now both carbs respond the same.

to start the car i turned al 4 screws out 2 Full turns , the car then idles but spits every now en then through carbs.

So i turn out each of them another 1.5 turns and that seems to be the cleanest idle. IF i turn them in half a turn again the idle goes lower and isn't as clean.

I would say that that is very close to your method.

But thanks for the advise.

i read up alot on the accelerator pump settings , one of my carbs has two little holes in so you have two places to put a pin in to hold spring ( I put it in wher it come off)

the other one wad two little nuts and it screws on. ( It was more or less the same as the other carb with the pin) so i just set it the same again.

I don't have any flat spots on acceleration and dit not have any beforehand so i just left it as is.

Next jobs:

1. Clutch is a but shuddery sometimes , I think it's due to worn rubbers on the engine mounts or on gearbox. There is a bit of gear lever back and fourth movement on pullaway. The shudder is VERY bad when trying to reverse. The engine mounts looked ok when i put the engine back in after the rebuild, But i haven't had a look at the gearbox mounting rubber. the clutch and plate itself is good , and was skimmed.

2. The rear seat is making a skeaking sound as i go over bumps ( VERY irritating!!!)

3. The rear shocks are new , but there is also a clicking sound when car goes trough bumps.

4. Gear lever is vibrating in gears 1 ,2,3, 4, i read somewhere ( it was somewhere in this forum) that i can drown the end part of the gear lever in grease, I want to try that.

5. The battery light is on ,very dim (can only see in dark) when lights are on, I read in this forum that i should run an extra positive wire from battery to fuses. I allready added another GOOD ground wire. from the battery to ground. One between the engine en ground is good enough.

I've only done about 60 miles after the engine rebuild and now carb clean and i LOVE the new found torque and smootheness in the fulvia engine. Trying to keep revs low and not accelerating hard for the first 1000km. All my oil leaks are Gone! There was A LOT of blowbye before rebuild.

Thanks for the help again.