Pict 34 carb and idling!

[milfredo]

Short story... Got van back on the road and could never get it to idle once warm. I spent days and days on it and eventually gave up and bought a new carb. Problem was sorted and the van was amazing all of the year.

I've rolled it out this year, checked valve gaps, ignition (found some loose plugs and changed HT leads), set timing to 30 dogs BTDC @ 3000 amp, vac off and plugged. Engine runs nice and smooth on the drive and nicely out onto the road but has soon as you come off the throttle approaching a junction, it just cuts out, almost immediately.

I guess I need the carb out to clean it but this seems so temperamental. I've never had this issue in any other of my VW's. Total PITA!

Any tips?

 

[sparkywig]

That sounds more like a manifold air leak.

 

[Elibomrod68]

Could just be blocked idle jet…
Rhs off carb just below the automatic choke. Can be easily removed on van - just dont short out the alternator!

Unscrew and clean with brake or carb cleaner

 

[milfredo]

That sounds more like a manifold air leak.

To test this, do I spray carb cleaner around the base of the manifolds to see if the engine revs pick up?

 

[milfredo]

Could just be blocked idle jet…
Rhs off carb just below the automatic choke. Can be easily removed on van - just dont short out the alternator!

Unscrew and clean with brake or carb cleaner

I did this today no problem... apart from shorting the alternator (seriously I did)

 

[Mechanoid]

Are you running points? Check that the gap hasn't closed up.

 

[milfredo]

No points, I have electronic ignition.

I was quite a miss mash, not too sure what exactly the problem was but it is mostly sorted;

I plugged the vacuum hose for the servo, removed the one way valve and couldn't'really blow in either direction but then it opened and worked as expected. Checked for air leaks with WD40 and the engine barely ticking over. Found none.
Found #1 wasn't firing so re-seated all new leads and also found that I had knocked off the fuel cut off solenoid wire (not too sure when) but with these back on, the van ran ok.
Tick over was very low so I backed out the idle air mixture screw until I got it to about 900rpm. It stank of fuel so the mix is all wrong but before I could set this I tried to time it but the gun I'm left with (my Dad has my nice one) means you need three arms to rev engine, turn the advance knob on the gun and then move the dizzy. I got it somewhere reasonable but need to come back to it.
I drove it for about 30 mins and it only conked out once and a junction. It didn't have much top end so advance is off and I think it is too rich. Things to do tomorrow!
I think it needs new intake boots as one side has minor cracks in it. Air is probably getting in there. This looks like a PITA job... does the engine need to come out?

 

[milfredo]

I cut off the air intake boots and one was completely swimming in fuel and was cracked.

I fitted the empi boots and everything seemed amazing until it wasn’t and the van started running like it’s got an air leak. I tightened the new boots up and it’s sort of ok but I think there is still a problem. What a ball ache.

Drove ok and no overpowering smell of fuel or conking but I guess the whole thing needs to come out.

 

[milfredo]

So I installed the empi boots and everything seems fine while on choke. It ticks over lovely, no hunting etc. once of choke and on idle, you get an uneven idle and if revved, it’ll almost go back to stalling. Is this still a symptom of an air leak despite not seeing any symptoms when on the choke?

Fuel pressure? Over feeling from accelerator pump? Or just an air leak?

What else to check on the carb?

This is starting to piss me off

 

[redgaz54]

So I installed the empi boots and everything seems fine while on choke. It ticks over lovely, no hunting etc. once of choke and on idle, you get an uneven idle and if revved, it’ll almost go back to stalling. Is this still a symptom of an air leak despite not seeing any symptoms when on the choke?

Fuel pressure? Over feeling from accelerator pump? Or just an air leak?

What else to check on the carb?

This is starting to piss me off

The setting for accelerator pump is usually middle diddle. I had cutting out at junctions when set to rich.
You need to check fuel pressure. Have you checked fuel level in carb?, adjusted by thickness of washer under float valve.
Is the choke fully open when warmed up?.
What distributor are you using?.
Have you got a standard oil bath air filter ?.

 

[milfredo]

The setting for accelerator pump is usually middle diddle. I had cutting out at junctions when set to rich.
You need to check fuel pressure. Have you checked fuel level in carb?, adjusted by thickness of washer under float valve.
Is the choke fully open when warmed up?.
What distributor are you using?.
Have you got a standard oil bath air filter ?.

It’s a new carb and I fitted it straight from the box. Embarrassed to say, all other setup steps skipped. I’ve not tested fuel pressure as I don’t have a gauge but I’m planning on getting one.
Choke is fully open when warmed up as it’s off the stepped cam.
Dizzy is a vac advance elec points one from Heritage. 32 degs @ 3000 revs, vac removed and plugged.

Carb setup next on books

 

[redgaz54]

The setting for accelerator pump is usually middle diddle. I had cutting out at junctions when set to rich.
You need to check fuel pressure. Have you checked fuel level in carb?, adjusted by thickness of washer under float valve.
Is the choke fully open when warmed up?.
What distributor are you using?.
Have you got a standard oil bath air filter ?.

It’s a new carb and I fitted it straight from the box. Embarrassed to say, all other setup steps skipped. I’ve not tested fuel pressure as I don’t have a gauge but I’m planning on getting one.
Choke is fully open when warmed up as it’s off the stepped cam.
Dizzy is a vac advance elec points one from Heritage. 32 degs @ 3000 revs, vac removed and plugged.

Carb setup next on books

That could well be your problem, the procedure is well documented as you'll already know . I went through pretty much the same experiences that you are now, the more i got most things back to standard, the better it ran, especially cold start up to warm / hot running, fully functional vacuum type oil bath filter highly recommended, plus working thermostat/ flaps etc, all tinware intact. I didn't have much joy with a Pertronix dizzy, ran ok but timing mark all over the place (strobe), ended up fitting a Bosch 034 with electronic ignition.My inlet boots were like yours when i cut em off, empi split boots cured erratic tick over. Incidentally, my engine is not happy ticking over under 1000 rpm. Anywayz, keep batting on, you will get there !.

 

[milfredo]

Someone cut off the oil bath stand so I can't fit it. I have a really lovely one in the shed that came with the van. It is one of my biggest gripes at the moment.

Mine runs fine at 1000revs and base carb settings. It just goes ***** when I fiddle it down to 850 and then try to get the fastest idle.

I read a new article that pretty much debunks the guide and gets you to a good place (post card setup that is).

Fun times tomorrow!

 

[redgaz54]

Someone cut off the oil bath stand so I can't fit it. I have a really lovely one in the shed that came with the van. It is one of my biggest gripes at the moment.

Mine runs fine at 1000revs and base carb settings. It just goes ***** when I fiddle it down to 850 and then try to get the fastest idle.

I read a new article that pretty much debunks the guide and gets you to a good place (post card setup that is).

Fun times tomorrow!

Good Luck with that As you know ,the air filter stand is usually cut out for twin carb set ups, but are often re instated too, just a thought, as without it your always sucking in cold air.

 

[milfredo]

So I checked the timing (for the 100th time) and then did the idle using my newly imprinted guide (not trying to idle at 850 and lean it out).

Took it for a drive and it is night and day better than before!

I still need to tune the carb but as a first fix, it seems OK!

 

[redgaz54]

So I checked the timing (for the 100th time) and then did the idle using my newly imprinted guide (not trying to idle at 850 and lean it out).

Took it for a drive and it is night and day better than before!

I still need to tune the carb but as a first fix, it seems OK!

Good news!. What's your, 'newly imprinted guide' ?

 

[milfredo]

This one…

Tihere are two adjusting screws that affect the idle...a small one for the volume of fuel entering the idle circuit and a larger one for the air bypass that controls the idle speed. They both must be adjusted together to obtain the correct idle speed. Don't be afraid to open these adjustments more than the 2 or 2 1/2 turns that the manuals say is correct. Just open them as far as you need to in order to get the motor to settle down to a decent idle. Also, once the motor's idling OK, don't bother trying to get the idle speed to drop by 25 RPM by closing down the volume screw a bit like the procedure says to do. Just leave it at the point where the motor is idling smooth at the highest RPM obtainable with that adjustment.

Pretty much what they all say but the bit about ignoring turning back the idle by 25-30 revs.

 

[redgaz54]

This one…

Tihere are two adjusting screws that affect the idle...a small one for the volume of fuel entering the idle circuit and a larger one for the air bypass that controls the idle speed. They both must be adjusted together to obtain the correct idle speed. Don't be afraid to open these adjustments more than the 2 or 2 1/2 turns that the manuals say is correct. Just open them as far as you need to in order to get the motor to settle down to a decent idle. Also, once the motor's idling OK, don't bother trying to get the idle speed to drop by 25 RPM by closing down the volume screw a bit like the procedure says to do. Just leave it at the point where the motor is idling smooth at the highest RPM obtainable with that adjustment.

Pretty much what they all say but the bit about ignoring turning back the idle by 25-30 revs.

Im well familiar with tuning carbs. With these Solex 34's i turn in small screw very slowly till revs just start to fall, then turn back out till it smooths out, the another half a turn, then set idle speed with large screw.
That said i usually hook up my CO meter, fine adjust if necessary to 3-4% CO (its usually ok anyway)
All said your only setting the idle mixture.
BTW i wouldn't set timing on a bus any higher than 30°.
Not just my opinion, advised by several vw experienced bods.
Good things are better now

 

[milfredo]

I'll wind it back 2 degs. Thanks for the advice.

I've found an air cleaner stand but it's in the US. I'll have to make it bolt-on somehow.

Carb tune this weekend and I think the bus will be more useable.

 

[NigelDenham]

I'll wind it back 2 degs. Thanks for the advice.

I've found an air cleaner stand but it's in the US. I'll have to make it bolt-on somehow.

Carb tune this weekend and I think the bus will be more useable.

I’m in the same boat, got a good oil bath filter, checked thermostat and flaps - all good…..but, no stand, it’s been cut off.
has anyone got a stash? I’ve been looking at fabricating something but it’d be nice to have a proper job.