Idle problems DVDA? SVDA? 34 Pict 3

[Timjones71]

The carburetor was just rebuilt by a mechanic friend of mine. I'm not saying that he couldn't have made a mistake, but are there any other things you would look at? If nothing else, I can always go back through it to make sure a mistake wasn't made or maybe he missed something.

[ashman40]

[wcfvw69]

[Timjones71]

I took off the carb and took off the top of the bowl. Inspected everything visually. Blew out passages replaced gasket on carb mount. Sprayed carb cleaner around all joints on intake manifold. No leaks heard. Very minor on the throttle linkage shaft. Sometime you'd hear a slight change in idle, sometimes not. I took out the air volume screw. Replaced o ring, threads are good. Took out the bigger idle screw, same, good. Dot of oil to get them both in and good slip fit, not a dry fit. Bottomed both out and started from 2.5 turns out. Started car cold. Same thing.... I held choke flap closed and it runs great. I turned air volume screw in all the way closed, still same. I checked all joints with carb spray while at this setting. No change. It's got to be getting air from somewhere. Has to breath. Choke fully closed, runs, even partially open will die. ARG!!!! What am I missing. I need a VW carb guy in the North of Nashville area.

[Timjones71]

Ok I took apart everything to check to see if mechanic missed something in cleaning process. We did do a gas tank removal and clean because of rust after it was rebuilt so there was a good chance maybe some rust or crud got past the fuel filter. All Jets were clean. Top air emulsion jet was a 75. Main jet in bottom of bowl was a 127.5 and pilot jet on side was a 55. All clean. When I took apart the Idle Cut Off Solenoid to blow out the passages I figured why not test it? DOESN'T WORK. Could this be the root of problem? Car runs at idle til warm then as choke starts to move car dies. Maybe it wasn't getting too much air. No vacuum leaks. Maybe it was starving for fuel? Please advise. I had a spare and I tested it on 12V, it functioned properly so I swapped it. Going to test after I put everything back together. [/b]

[David_nc_72std]

[Timjones71]

That was it! Bad idle cut off solenoid. Switched it out. Problem solved. It started up and I was able to adjust from factory settings. Thx to all.

[mrkrause]

Yep.....I’ve got a 1600 DP, solex 34, 009 distributor.......same problem once the screw drops down to the bottom of fast idle cam, engine won’t idle anymore....just dies.

Today:
-Lashed the valves to .006
-new NGK B6HS plugs gaped to .026
-new plug wires
-replaced points, set at .016.....check with dwell/ tach 48°
-new rotor and cap
-set timing advance about 5°

I read this thread tonight....ran back out to check idle cutoff solenoid. Turned key to on, pulled wire terminal off solenoid and retouched it “click” ......sounds like it’s working.

I have a fuel pressure regulator with gauge on this motor.......running about 2# psi.

After warming up......with the top set screw (bypass) a couple turns out, and the bottom screw(volume or fuel/air mixture) 2 1/2 turns out.....the butterfly is fully open.....I gotta keep a finger on the throttle to keep it running. And even while keeping it running, turning the bypass or fuel/Air screws makes no difference at all.

What am I missing?

[ashman40]

[wcfvw69]

"IF" you are 100% sure you don't have any obvious vacuum leaks and the carb is adjusted correctly, in all likelihood, you have something clogging the idle circuit in the carb. One note though. Everyone assumes you have to be in the 2.5 turns from closed on the volume adjustment screw. In some cases, you have to open it up to 3 or even 3.5 turns out to achieve idle.

The best way to clean the carb is to totally disassemble it. Then put all the parts in an ultrasonic parts cleaner with hot water and degreaser. Run it for 30 minutes and it will vibrate all the tiny passage clean.

Pull from the ultrasonic machine, rinse off in clean water and then blow all the passages out with compressed air. Make sure all the jets are clean and clear, reassemble and try again.
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[vamram]

More than 4 turns out is not unusual as a base starting point on a 34-3 or 34-4, even volkzbitz instructions used to recommend that for the two I bought from him a few years back.
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[mrkrause]

Ashman40......it is 5° BTDC.


This carb was taken apart and cleaned not too long ago, but we’ll do it again. I’ll try to find someone who has an ultra sonic parts cleaner.....or I’ll just get some Berryman and soak it overnight, then blow it out well.

This buggy was running fine until the last day on a 3 day buggy event. Started back firing going down hills, and stalling at interesections or while not under load.

[vamram]

[mrkrause]

So.......completely disassembled carburetor.....soaked overnight in Berryman.....reassembled......New o-rings on bypass screw and volume screw (they were completely shot).....

After I reinstalled the carburetor....started it up.....let it warm up.....still wouldn’t idle until I backed the pilot jet out a half turn. I pulled the pilot jet off found a thin washer that would keep the pilot jet held out a little. Now it would idle so I could check timing, readjust bypass & volume screws and BAM ! We are back in business !!

I’m glad it’s running smooth again, but it’s killing me that it came down to a dirty carburetor. I put a premium fuel filter on it time, so hopefully this issue won’t repeat for awhile. Plus I now know the condition and status of all the components I either replaced or adjusted.

I appreciate all the help and advise y'all have given me !

Ken Krause

[bnam]

If the retard side of a DVDA can fails and I decide to use it like an SVDA can timed at 7.5deg, Does the carb throttle plate hole now need to be made smaller with a rivet? Or is there something else that's different between the DVDA and SVDA allow the carb to work well in "SVDA" mode with a DVDA distributor?
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[ashman40]

[glutamodo]

I just noticed that I'm not seeing the "hole size image" where I went and used precision 21 and 30 drill bits in DVDA and SVDA throttle butterflys - I've posted this image many times in such threads but I'm rather surprised to see I did not do it here. And so, here it is!

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[63vdubbug]

Hello - Bringing up an old thread here. Needing suggestions. My bug is older with a 1600 SP. Just purchased a SVDA (Pertronix) and got a deal on a Solex (german) 34 pict 3 carb which looks to be in great shape, very clean.

After doing some research I may have a 34 pict 3 for a DVDA distributor. Getting ready to rebuild the carb, but wanted to know if I should already tackle by making the hole smaller on the lower throttle plate mentioned in this thread? or, should I look for a 34 pict 3 specifically for a SVDA.

[kreemoweet]

It's quick and easy to throw a rivet in the throttle plate hole. If that doesn't do the trick, it's also
quick and easy to remove it. I have SVDA dist., and I completely blocked hole in 34 PICT-3 plate with rivet, best thing I ever did. Carb always adjusts perfect now, had endless problems before.
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[63vdubbug]