1600dp won't idle, where to start

[Hg1027]

Hi there Forum

I got a 72 beetle that hadn't run in about 5 years, and I've started and run it a few times over the last couple weeks. It will stay running at ~2krpm, but any lower and it dies. It appears to be fuel starved at lower rpm.

It has a 34 pict 3 and a 009, which I understand do not usually play well together. The carb looks relatively new (a neighbor opened it up to clean the bowl and be sure the float was loose, he did not note jetting), the distributor looks a little older just judging by corrosion on the body.

Side note of possible importance, the blue coil that was on it was not putting out anything, so it was replaced with one from autozone that claims a 3 ohm ballast. This coil gets uncomfortably hot (haven't measured, less than 3 seconds) when running. No issue with just the ignition on, not running.

My next options appear to be:

1. Replace the coil with a new blue bosch. I've read conflicting reports that the only difference is color.

2. Open the carb and check the jetting. I do not really want to go the route of jetting the 34 to work with the 009, as I understand this kills mpg, and we're going endurance racing. This would only make sense if I'm going to keep the carb and swap the dist. I do not want to get in to dual carbs, as I need reliability and easy tuning. I would consider a used carb if I'm told this carb is not what I need at all.

3. Order a new distributor. I believe I want a svda, I have not looked at model numbers, but jbugs and aircooled.net both seem to have pertonix units for about 150.

We have adjusted both screws on the 34 all the way in, backed out by half turns, no improvement, and moved timing forward and backward a few degrees, no improvement.

So, where do I start?

[Brian]

You can make what you have work. Don't buy anew ignition kit from jbugs unless you know what you need. The carb is more than likely dirty and the idle jet is probably plugged. You can get a rebuild kit for relatively cheap. Tear it apart and clean it really well. There are a billion diagrams online with exploded views to assist you. Static time the motor, then rev it up to 3k and check your dwell angle and your timing. Adjust as needed, then tune your carb. There's a really good vintage video that does an excellent job explaining what needs to be done. I'd post it but I'm too lazy to find it.

Good luck
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[David_nc_72std]

First suggestion is to make sure the idle cutoff solenoid is working, and that you didn't forget to reconnect the wire when you changed the ignition coil.

As was mentioned, the idle jet could be plugged, or the auxiliary jet (located behind a screw plug right beside the idle jet). 34 pict 3 carburetors are also know for developing vacuum leaks around the throttle shaft (the original bushings are plastic and tend to wear out after 40 years).

[Hg1027]

The idle cutoff solenoid was cut, so no issue there. I'll check the jets tomorrow evening.

Regarding the throttle shaft, I'm not sure how to check that. I had intended to spray starting fluid around it once we had it running at any rpm, but that wasn't happening. Would an oring or some silicon work long enough to confirm?

This carb looks fairly new - certainly not 40 years old, maybe not even 10. Is there a way to cross check a serial number? Is there a serial number? I'll post what numbers and words it has later today.

[Hg1027]

I pulled the idle jet, which is clear, #55, but there's no oring on it. Is there supposed to be? It looks like it should have one.

[Beeble1]

I believe this is the video, Brian.

https://youtu.be/XOxxS1EMphU
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Beeble1, ‘73 Super (o\_|_/o) 1600cc w/ Dealer A/C
Beeble2, ‘13 Beetle 2.5L Daily Driver

Dealership items from Bishop-Wayne Volkswagen & Turner Volkswagen in Kankakee, IL wanted

[jason_hamilton]

This document does a pretty good job of explaining how the carb works under various loads.
(Section 3-6, page A-9, 30/34 PICT-3 idle operation).
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1969 Karmann Ghia coupe
@MiddleAgedHoon

[David_nc_72std]

[Hg1027]

Bocar 113 129 021p.

Going to check the auxiliary jet.

[glutamodo]

Bocar 34s don't have a great reputation. I've never cared much for them.

I've never understood why this is, but sometimes these style "Solex" carbs just won't idle with the idle fuel (pilot) jet tight. Loosen it slightly and, boom, they start idling. Some people have to Loctite the jet in place just slightly loosened from all the way tight.

Yes, the auxiliary jet is part of VWs attempt at tighter emissions control so they split the idle into two pathways, and it is needed for the idle to function. Also, note that the idle and auxiliary fuel circuits have air jets that are built into the carburetor, facing upward.

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Andy T.


IMAGE NOTE: It has been noted that Chrome based browsers may have issues in displaying my vast image library, which use non-secure links and are on an FTP server. Images should still be viewable if the link is clicked though.
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[Hg1027]

Thanks again for the replies, I'll try the loosened idle jet this evening.

Also, after pulling the screw out of the auxiliary jet hole, and loosening the jet, it doesn't come out. Any trick to that?

[glutamodo]

if the carb is on the engine, it won't come out. You have to shake it out.
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Andy T.


IMAGE NOTE: It has been noted that Chrome based browsers may have issues in displaying my vast image library, which use non-secure links and are on an FTP server. Images should still be viewable if the link is clicked though.
I do not know how to fix this. All I can say is it all works fine for me with what I use, Firefox.

[zoobyshoe]

[wcfvw69]

I have several 34-3's that wouldn't idle off choke. It took an ultrasonic part cleaner to really clean the idle circuit out. Once it was clean, all of them idled correctly.

If you have to crack the pilot/idle jet for it to idle, you have something blocking that circuit that needs to be cleaned out.
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