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I just rebuilt the 30 pict that is on my car. According to the carb adj. info I have the idle speed is adj’d. by the large air by pass screw on the side of the carb and the fine tune is done by the small needle screw right next to it. The car will start fine, but when I try to set the idle at 850 rpm with the large adj. screw…it has no impact on the idle speed. I can screw it almost all the way in and it will decrease the isle to about 200-300 rpm, but I can also screw it almost all the way out and the idle doesn’t increase. Basically nothing much happens when I adj. with the large idle adj. screw. Any words of wisdom regarding a fix for this issue?
Samhttp://www.vw-resource.com/carb.html#30
Single adjustment screw pict30:
http://www.vw-resource.com/30PICT2.htmlTwo adjustment screw:
http://www.vw-resource.com/34pict3.htmlPaul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica RoadsterIf you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)
Do you have a electronic idle shut off screw on the right side of your carb. or a mechanical screw in place.
I have a 30 pict carb and could never get it to work right, until I replaced the electronic idle shut off with a mechanical one.
The adjustment screw on the left side of the carb. didn’t work correctly until I changed it out. Then it worked like a charm, go figure.
Only other thing maybe a vacuum leak at the base of the carb. which I also had because the manifold was not flush with the carb. base and had to be filed it level and re-place the gasket.
Hope this helps. Mark
You May want to blow some air through the idle jet seats in the carb, they can get gummed up when carb cleaner is used. Did you use the gallon bucket of carb stuff you let the parts soak in? That stuff gets out all the junk, then you blow the ports out with an air hose after soaking.
Thanks to all responses. I’m going to pull the carb back off and recheck everything just in case I missed something and then re-install and see what happens. Will post an update or ask more questions when that is done.
SamOk. Took the carb off and recheck, etc. Did find a gasket that I forgot to replace, so did that and re-cleaned and re-installed the carb. Started with the initial settings of 2 turns out on the air bypass/idle adj.(large screw) and 2 1/2 turns out on the small adj. screw. Car starts fine and was at 1000 rpm and then dropped to 800 rpm after warm up. Tried to adj. the air bypass/idle screw out to increase the rpm to 850-900, but there wasn’t any noticible change in rpm. Then just turned the bypass/idle screw almost all the way out and still no incr. in rpm. If I let it continue to idle and don’t touch the throttle, the rpm’s drop off to the 600 range. If I then manually hit the throttle and take the revs up to 3000 and let it come back down, it settles at 800 rpm, but it will eventually start dropping back to the 600 range. I did try to adj. the small needle about 1/2 a turn out as suggested, but didn’t see any change so didn’t mess with it anymore as the bypass/idle adj. still doesn’t seem right. Any bright ideas? Thanks.
SamOk..still having carb problems. I noticed that on the new 34 pict carb I have that there wasn’t any adjustment to the accel pump mechanism on the right side of the carb, but on the 30 pict carb that was on the car there was a nylon nut that screwed up against the spring allowing for some adjustment to the spring tension and since my car didn’t seem to want to accel. without shifting to a lower gear, I decided to adjust it and the result was the car ran worst. So, since I had the new 34, I thought why not just put the new carb on and be done with it. Set the carb up per the link on 34 carbs Paul listed above and the good news is it started right up, the bad news is no matter how far I screw the by pass screw in or out, the rpm won’t go above 400 rpm and it barely will keep running at that speed. The timing is right, don’t see any gas leaks….I give up. Help!!
Sam
Sam I’ll PM you when I get home from work with the adjustment procedures that came with my 34PICT3 rebuild kit. Also on the 34PICT3 carb the accel pump volume can be adjusted. I’ll include that procedure as well.
Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackSam. Here are the two links I use. The match the procedures you get with a 34PICT3 carb rebuild kit. Can’t locate mine. I’ll have to order another kit.
Adjusting the 34PICT3 Carburetor
http://www.vw-resource.com/34pict3.html
Accelerator Pump Adjustment
http://www.vw-resource.com/acclrtr3.html
newkitman2013-09-24 19:18:10
Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackAllen, thanks. The adj link for the 34 carb is the one I followed and still can’t get the idle set. As I mentioned, the by pass screw has no affect on the idle rpm at all. If I can ever get the idle set, I’ll have to look at the accel pump adj as my car does have a non vac adv distr. In the mean time I’m still stuck at square one with no idle adj.
Sam
Timing is right, you say? How do you know? Is it static timed with a test light?
If so, vacuum leak?Since you found one gasket you’d missed . . . .I’d check every connection on the intake side, from the carb to the heads. Make sure it’s all tight and then maybe test with some starter fluid.Are you running a 009 (mechanical advance) distributor or a vacuum advanced distributor? The 34PICT carb does not like working with mechanical advance distributors. Idle problems and hesitation are the two biggest ones. The 34PICT was designed to work with the dual vacuum advance distributors. They can be adjusted to work with the 009 distributor but it gets a tad bit touchy.
Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackEd, I had been through the timing set up for a mech adv. distr. with Roy right after I got the car, so sure that is ok. The gasket I missed was on the 30 PICT rebuild. The 34 is new out of the box carb a buddy gave me. I will re-check the vacuum connections. The 30 pict carb was running “ok” but as I mentioned it seemed to lag when I tried to accel. while in a higher gear so I adjusted the accel. pump on the 30 pict (not really knowing what I was doing) and it ran worse so I tried the new 34 pict.
Allen, yes it is a mech adv. distr., so given what you said about the carb not working well with the mech adv. distr., I think for now I’ll go back to the 30 pict carb. Hopefully I can get the accel. pump adj. back to where it was so it will at least run “ok”.
Sam
I’m running a single vacuum advance distributor with my 34PICT3 carb. I’ve just had few problems if any with that combo. But it’s your choice. If you go back to the 30PICT carb, adjust the accel pump like it says in the link I posted. Also set up the carb following the posted links from Rob and Dave’s VW pages. Can’t remember if the 30PICT barb has a hole in the throttle plate in the bottom of the carb. Check it out on your carb and see if it has the hole in it. Some folks have riveted or silver soldered the hole with good results.
Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackYes they are separate issues. Its just those two seem to be the most prevalent when running a 34PICT carb with an 009 distributor.
Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackI don’t run a 34PICT carb any more, but when I did I made the modification described in link and it considerably improved performance and eliminated the flat spot. I used a pop rivet instead of solder. When I rebuilt engine to 1776 cc I went to a webber progressive.
Ok, here is where I stand. In the process of changing back to the 30 pict carb I discovered a bad spark plug wire, so got a new set of wires and distr. cap and installed them. I set the 30 pict up (again) per the link above with the vol scrw out 2 1/2 turns and the by pass scrw out at 2 turns. When I started the car and warmed it up and couldn’t get the rpms above about 400 rpm on the tach. I finally adjusted the volume scrw in (according to the link I should have done this after I set the idle with the by pass, but nothing else was working)about one turn and then went back to the by pass scrw and was finally able to get the idle at 900 on the tach. Also, in the process I rechecked the timing and it was dead on at 3000 rpm. I then took it for a test drive and it seemed to run a little better ( I won’t say great as there is some lag when accel’g.) I do have one new issue in that I get a back fire sometimes when I accel. in 3rd gear, so all is not well yet. Allen, the accel pump adj info you sent me is for the 34 pict with the mech adv. distr. So not sure it applies to the 30 pict, correct? Anyhow I’m still open to any further suggestions to get it running a little more smoothly.
Sam
The 30 pict carb is usually a fairly mild-mannered thing and easy to tune, at least compared to the 34! Myself I would rather run a 30 and suffer the small loss in power than put up with the nonsense the 34 is capable of. The 30 pict is usually way to lean on the main jet for smooth power, it probably worked ok with a new, tight engine but most of ours require a 127.5 or 130 main jet to get them running good! Try it, you’ll like the increase in power AND the engine will run a little cooler.
Eddy, it sounds like this is worth a try. I’m not a carb guy so if you or anybody can point me to where I can find out how to change the main jet and where to buy the 127.5 or 130 main jet it would be appreciated. Thanks.
Sam
Sam…sent you a PM with the instructions that came with the carb rebuild kit. It covers theses carbs: 28PICT-1, -2,30PICT-1, -2, -3 and 34PICT-3 and -4.
Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackI just drilled my main jet out with a 55 drill bit. A very nice improvement in performance a drivability, possibly some loss of fuel economy but I’m still getting better than 25 us MPG. Some people reduce the power jet to 50- 55 but I left mine alone, I’m not into the power jet very often! ( I drive my car fairly easy)
Eddy, thanks. Perhaps when I get the info from Allen, it will show me the main jet and I’ll drill it per your note.
Sam
Accelerator Pump Adjustment
http://www.vw-resource.com/acclrtr3.html
Allen gave me the above link for adjusting the accel pump on a 34 pict for use with a mech adv. distr. Does anybody know if this adjustment procedure also applies to the 30 pict 3 carb when using a mech adv distr? Thanks.
Sam
Sam,
That procedure should work for the 30 PICT as well but I’m not sure of the accel pump volume limits. Just as long as the accelerator pump in not positioned at the rear of the carb like the 28s to 30PICT1. I can’t see why the 30PICT-2, -3 and 34PICT-3 and -4 shouldn’t work.newkitman2013-09-29 11:19:59
Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The Shack
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