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aircoolfreak Samba Member
Joined: October 25, 2006 Posts: 183 Location: Lees Summit
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streetboy Samba Member
Joined: February 08, 2009 Posts: 21 Location: UK
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Posted: Sat Aug 07, 2010 1:40 pm Post subject: Idle adjust on 34-PICT-3 |
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I have found this thread a life saver
I have had an ongoing issue with a slight stumble come flutter when driving around 25/30mph. To say I have done/replaced everything you could imagine and still could not sort it out. If I gave it gas it would pull through the flutter and fly.
Thats when I read through this thread and comments about the idle jet being overtightened. So I gave it a shot, cracked it off, took it out two turns and gently wound it back in till it only just made contact with the carb body. Took it for a drive and that annoying hesitation has gone
But what I need to know is why? the bus has always idled and revved from idle but as soon as the magic 30mph came in (and more noticable on an incline) it would start a rythmic fluttering. So whats going on? |
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webrx Samba Member
Joined: August 10, 2010 Posts: 18 Location: Reno, NV
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Posted: Thu Aug 12, 2010 9:28 pm Post subject: |
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redeye65 wrote: |
I have had success using the BugMe DVD settings for my pict 34-3.
I remove the large idle and small richness screws, then remove the jet/s on the other side. Then sprayed our the whole carb and the removed parts with carb cleaner. Bottom out all screws, then back off the large idle screw 5 full turns, and the little screw 10 turns. Then adjust the little screw as needed.
My jet seems to work fine snugged up. |
Hi, new guy here...
I have a solex 34 pict 3 and this actually seems to be closer for me. Not sure why, but at 2.5 to 3 turns out on both screws the bug (73 standard) will not idle at all warm or cold (I know this is just a starting point). If I start unscrewing the little screw (mixture) riching it up, then the car comes into a spot where it will idle, seems to be somewhere around 5 to 6 turns out that it will idle. No vacuum leaks that I can find, though I am pretty sure it is going to need new points, plugs, condenser, cap rotor, etc. as I am reviving it from a po who obviously did no maintenance to the vehicle.
Assuming I do the above tune-up and adjust the valves (needs a new cover gasket anyway). I want to understand the whole process so lets see if I got it please.
Once fully warm, do you continue unscrewing the mixture to find the highest idle (adjusting down the idle screw - big one - every now and then) until it no longer increases RPM and then tweak it in just a hair, set the idle with the idle screw (big one), give it one final plus or minus 1/8 turn to find the sweet spot and call it quits? or is there more I am missing? I am looking for the best spot for smooth idle and no flat spots when driving (aren't we all)?
thanks,
Dave |
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keifernet Samba Search & Rescue
Joined: May 11, 2002 Posts: 19395 Location: Samba Center for Behavioral Science
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Posted: Fri Aug 13, 2010 7:52 pm Post subject: |
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webrx wrote: |
redeye65 wrote: |
I have had success using the BugMe DVD settings for my pict 34-3.
I remove the large idle and small richness screws, then remove the jet/s on the other side. Then sprayed our the whole carb and the removed parts with carb cleaner. Bottom out all screws, then back off the large idle screw 5 full turns, and the little screw 10 turns. Then adjust the little screw as needed.
My jet seems to work fine snugged up. |
Hi, new guy here...
I have a solex 34 pict 3 and this actually seems to be closer for me. Not sure why, but at 2.5 to 3 turns out on both screws the bug (73 standard) will not idle at all warm or cold (I know this is just a starting point). If I start unscrewing the little screw (mixture) riching it up, then the car comes into a spot where it will idle, seems to be somewhere around 5 to 6 turns out that it will idle. No vacuum leaks that I can find, though I am pretty sure it is going to need new points, plugs, condenser, cap rotor, etc. as I am reviving it from a po who obviously did no maintenance to the vehicle.
Assuming I do the above tune-up and adjust the valves (needs a new cover gasket anyway). I want to understand the whole process so lets see if I got it please.
Once fully warm, do you continue unscrewing the mixture to find the highest idle (adjusting down the idle screw - big one - every now and then) until it no longer increases RPM and then tweak it in just a hair, set the idle with the idle screw (big one), give it one final plus or minus 1/8 turn to find the sweet spot and call it quits? or is there more I am missing? I am looking for the best spot for smooth idle and no flat spots when driving (aren't we all)?
thanks,
Dave |
While there is tuning info on the two screws on the left side of the carb, ( the big brass air bypass and the smaller mixture screw) the "sweet spot"
is in reference to the idle pilot jet and not those two screws.
Read the entire thread again and see... there are several factors that can be present when trying to tune one of the different 34 pict 3 Solex carbs... |
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webrx Samba Member
Joined: August 10, 2010 Posts: 18 Location: Reno, NV
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Posted: Fri Aug 13, 2010 10:24 pm Post subject: |
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Thanks for the reply, having read the thread at least twice, I understand that a lot of it refers to the right hand brass screw and how this can smooth out idle.
I am looking for the right position of the two left hand screws and maybe "sweet spot" was the wrong way to ask. I am assuming after reading this thread and all the linked threads, that you keep backing out on the smaller screw until RPM stops going up. then use the big screw to set the idle, then tweak in the small screw until idle drops 30-40 rpm. then reset the idle. Wanted to be sure I had this correct.
Thanks
d |
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borninabus Samba R&D Dept.
Joined: May 18, 2006 Posts: 4536 Location: Arizona Highways
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Posted: Sat Aug 14, 2010 12:04 am Post subject: |
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carb adjustment is the last step in a complete tune up.
come back to it after you have done so and you will find it a lot more responsive to tuning
basically reset all three adjustment screws per bentley.
run the mixture (small) screw in until idle drops slightly then back it out 1.5-2.5 turns.
where ever it seems smoothest.
then reset idle if needed with the bypass (big) screw.
leave the screw on the end of the throttle arm at contact + 1/4 turn.
DO NOT set the idle using that screw.
welcome _________________ 88 Van WBX, A/T - 13 JSW TDI 6M/T - 2012 Touareg TDI Sport |
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CLASSIC CAR GUY Transport and Title Guru
Joined: August 09, 2010 Posts: 1608 Location: Phoenix AZ, but originally from Long Island NY
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Posted: Tue Aug 24, 2010 11:38 pm Post subject: |
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THANK GOD WHAT A GOOD THREAD!!! I was going to see about adjusting my carb, came here to search first glad I did , also found another good tech site for doing this carb adjustment!!
http://www.vw-resource.com/34pict3.html#carb _________________ (0\!/0)
58' Rag'
60' Type 1
61' Type 1
62' Type 1
64' Type 1
66' Type 1
66' Vert'
67' Type 1
"every one wants to reinvent the wheel, but nobody knows how to make it round"
Vintage Volkswagen Sales and Service as well as Classics and Muslcecars all located here in Phoenix Arizona at www.rpmotorcars.com |
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Desertbusman Samba Member
Joined: June 03, 2005 Posts: 14655 Location: Arizona
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Posted: Wed Aug 25, 2010 12:00 am Post subject: |
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Save time on adjusting your carb by just opening your service manual and following the instructions. _________________ 71 Superbug
71 Westy |
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dti Samba Member
Joined: February 26, 2009 Posts: 154 Location: Penngrove, California
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Posted: Thu Aug 26, 2010 1:53 am Post subject: |
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Okay, I am baffled, but I finally have a bus that idles. Recently I purchased an SVDA and a 34 pict 3 from Aircooled.net. I have a '70 kombi, made a camper by Riviera, and somewhere in the last 39 years a 1600 dp engine made its way in there.
As found, it had the original 1970 vacuum only distributor paired with a Brazilian 30/31 carb. I have been gradually learning it and getting it to run better than it did when we met. I never was happy with the combination of distributor and carb, and finally went with the SVDA / 34pict3 combo as those are what I understand the dual port engine likes best. It did finally lose the last of the off-idle nosedive it still had after I beat the coal out of the intake manifold heat riser. But now, it would only idle for twenty seconds or so, and then needed a lot of pedal to keep running. When I had a dead idle solenoid last year I could keep it alive with less pedal than it needed now, and this time its a brand new carb and the solenoid clicked smartly when I played with the wire.
Finally after running through the Bentley, checking the ideas in this thread, and doing all the tuneup first, in order, by the book, it just died every time I took my foot off the gas. So I unsnugged the idle jet again. I had it out to clean it and blow it out already, but this time I loosened it about a quarter turn, like a lot of the people in this thread did.
It idled like the proverbial sewing machine.
So I put a dab of JB Weld on it to keep it from unscrewing, and I have a bus that doesn't act like it wants to play stoplight dragrace. All possible due respect to the engineers, the Bentley, and DBM, but I had no real other choice after playing out all the correct moves without good results... _________________ 1970 Riviera 1600 DP
1996 Ducati 900 Monster |
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borninabus Samba R&D Dept.
Joined: May 18, 2006 Posts: 4536 Location: Arizona Highways
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Posted: Thu Aug 26, 2010 6:37 am Post subject: |
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i see the idle jet problem a lot with replacement carbs.
hardly ever with the OG ones. _________________ 88 Van WBX, A/T - 13 JSW TDI 6M/T - 2012 Touareg TDI Sport |
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dti Samba Member
Joined: February 26, 2009 Posts: 154 Location: Penngrove, California
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Posted: Thu Aug 26, 2010 6:15 pm Post subject: |
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Mine came with a Brosol, I couldn't even guess when it lost the original Solex it came with. It's just odd that a new carb from a reputable supplier needs a bodge to work as intended... _________________ 1970 Riviera 1600 DP
1996 Ducati 900 Monster |
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borninabus Samba R&D Dept.
Joined: May 18, 2006 Posts: 4536 Location: Arizona Highways
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thomas. Samba Member
Joined: July 31, 2010 Posts: 1290 Location: South West (Pa.)
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Posted: Thu Sep 09, 2010 4:54 pm Post subject: idle problems |
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I've got a'62 bug (6 volt)with a '65 engine in it that I bought 2 mos. ago that stalls when I come to a stop & neither screw makes any difference when I adjust.(volume or idle bypass)Its an H30/31 with a 009 dist. Can't find any vacuum leaks, the preheater pipes get warm,tried backing off the idle jets(straight & angled) on right side with no results.Carb looked new when I bought.So...I take carb off yesterday to get a better look & clean all the screws & whatnot.Turns out the choke element is 12 volt & I assume the cut off too.Timing ,dwell, valves all have been triple checked. Other than the stalling out it runs good and the plugs are probably carbon fouled again by now. Any thoughts or suggestions ? Thanks in advance |
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BDSBSS23 Samba Member
Joined: January 03, 2008 Posts: 1817 Location: Colorado
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TUDrewser Samba Member
Joined: July 17, 2005 Posts: 238 Location: Mesa, AZ
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Posted: Mon Oct 18, 2010 4:41 pm Post subject: Re: idle problems |
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beryl green'62bug wrote: |
I've got a'62 bug (6 volt)with a '65 engine in it that I bought 2 mos. ago that stalls when I come to a stop & neither screw makes any difference when I adjust.(volume or idle bypass)Its an H30/31 with a 009 dist. Can't find any vacuum leaks, the preheater pipes get warm,tried backing off the idle jets(straight & angled) on right side with no results.Carb looked new when I bought.So...I take carb off yesterday to get a better look & clean all the screws & whatnot.Turns out the choke element is 12 volt & I assume the cut off too.Timing ,dwell, valves all have been triple checked. Other than the stalling out it runs good and the plugs are probably carbon fouled again by now. Any thoughts or suggestions ? Thanks in advance |
I had the same thing, as far as stalling as I came to a stop. Would feather the gas and it would start idling again. Wierd thing was that for the last week since I put the rebuilt (German) 34 pict3 ont was driving and idling better than it ever had. Then today, nothing. Screws did nothing, couldn't set RPM, stalled on stop. Backed the idle jet out just a tad and the sputtering idle roared backup. Adjusted RPM back down (went from 700 to 1900 with a tad turn of the jet) and all is now well. Amazing. |
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dcnjoe60 Samba Member
Joined: March 26, 2008 Posts: 434 Location: Missouri
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Posted: Sat Nov 06, 2010 9:53 am Post subject: Don't forget to check the accelerator cable |
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I've been struggling with trying to get my 34-pict-3 to idle properly and to adjust my svda. No matter what I did, I could not get my idle down below 1100 unless I really messed with the volume control screw. The bypass wouldn't do anything at all. Of course, then it would run rougher than you know what and die when giving it gas.
I was about to yank the carb and rebuild it when I noticed that the throttle was not returning to all the way closed position. It turned out that the cable from the pedal to the throttle was adjusted to tightly -- I assume the po thought that would get maximum power. This also had the problem of causing the vacuum advance to be advancing at idle, instead of 0.
Anyway, the amount it was not returning was not large, less than the full first step on the fast idle cam, but more than the fraction of a mm it is supposed to be.
Anyway, I know this a a long thread and the original poster hopefully solved his problem years ago, but I thought I would add this one thing to check before messing with jets and air mixture, etc. |
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andrewsanteiro Samba Member
Joined: July 07, 2009 Posts: 273 Location: Pisgah Forest, NC
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Posted: Thu Dec 30, 2010 9:59 pm Post subject: |
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I backed out screw B in this picture a 1/4 turn or so and got my 1600dp with vacuum advance idling after attempting many other per procedure tinkerings... my only concern is that I am confused as to what exactly this is I am doing by adjusting this that is "fixing" the problem, and wanted to know that I am not just masking another problem?
I read others have done similar and so I dropped a few drips of blue thread locker near the gap of where the (B) adjuster screw met with the body of the carb. (if this was a bad idea and I need to address this, please warn me.) _________________ On the road. Thanks to the Samba!
72' 1600cc Baja Bug |
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don.ville Samba YardMan
Joined: February 07, 2008 Posts: 2829 Location: West Palm Beach, FL
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Posted: Fri Dec 31, 2010 6:55 am Post subject: Re: Don't forget to check the accelerator cable |
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dcnjoe60 wrote: |
...
I was about to yank the carb and rebuild it when I noticed that the throttle was not returning to all the way closed position. It turned out that the cable from the pedal to the throttle was adjusted to tightly -- I assume the po thought that would get maximum power. This also had the problem of causing the vacuum advance to be advancing at idle, instead of 0.
... |
I had thas same issue too.
don.ville wrote: |
Still running the German VW Solex 34 pict 3.
Backed out the idle jet 1/2 turn and added some goop to keep in in place.
Found out I had a slight amount of tension on the throttle cable making the idle erratic, and as the cable stretched/shrank, it would affect idle speed.
I backed off the 8mm nut, released all the tension, and tightened it back.
Idles consistently now. |
We are beyond helping the original poster now. The additional information is for people that do a search and find this thread. _________________
67 Standard 11 window How I Keep My Bus Alive
04 Jetta TDI Page (SOLD)
01 Mexican Beetle Hello Kitty Rescue (SOLD)
29 Ford Model A Rat Rod (SOLD)
2015 Audi A8L TDI Quattro
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AWatry Samba Member
Joined: January 07, 2011 Posts: 9 Location: Berkeley, CA
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Posted: Tue Jan 18, 2011 11:01 am Post subject: |
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I just got my 71 DP 1600 with 34 carb running after little use in the past few years. Had the engine out to fix oil leaks, clutch, etc.
It idles fine, and pulls well once it catches its breath, but in the transition phase from idle onward it really falls on its face. I presume this is the famous DP flat spot? It's really hard to drive through. I had a SP 1600 with 30 carb for 15 years and had no such issues.
I did a valve adjustment, set points, and timing is set to 6* BTDC. The throttle positioner was disconnected and orifices capped off. Has stock vacuum advance dist. I don't feel any suction coming out of the vacuum port on the carb; there should be some, right? With a timing light on it, the dist seems to advance at the same rate whether the vacuum line is connected or not. So I might be getting mechanical advance only, no vacuum? Would working vacuum advance fix the flat spot?
In terms of the screws, the idle mixture screw was 5 turns out from seated, and the idle air screw was about 1 turn out. The mixture screw seems awfully far out, but it runs poorly when screwed in to the 2.5/3 turns recommended in the book.
Any help appreciated here. I'm thinking a carb kit in the 34 is Step One, Step Two is making sure I'm getting vacuum suction, Step Three putting the dist on a dist machine to see if vacuum advance works.
Andrew |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51120 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Tue Jan 18, 2011 11:25 am Post subject: |
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The advance could be part of the issue but 5 turns is a lot for the mixture screw, sure you don't have any vacuum leaks?
Try sucking on the hose to the advance on the distributor, it should hold a vacuum and if you suck hard you should see the plate the points are attached to move a bit, also try that on the retard hose. If either won't hold a vacuum you'll need a new vacuum can (assuming the hoses aren't leaking). _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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