VW bug solex carb idle adjustment?

This is a 66 beetle which has a 1600 built by a local shop before we got it. The carb is a solex H30/31PICT. I think it only has about 3000 miles on the new engine, and according to the previous owners it ran fine. When my mom drove it home it wouldnt idle when it was warm, it would just die. You can get it to barely idle when the choke is open if you turn the adjustment screw on the choke plate all the way in, but then it runs at like 3000 rpm when its cold. The proper way is supposed to be with the idle air and idle mixture screws on the side of the carb, but they do nothing. Any ideas? And did I mention i hate carbs? lol

good reference source for AC VWs:

http://www.vw-resource.com/index.html

Thanks, that looks like some useful info. I am pretty sure there is something wrong with the carb though, its not a stock one for one thing, and I found several places with instructions of how to set the idle, but the adjustments dont do anything when I tried it. The distributor isnt stock either, so it may be kinda annoying to get the car to actually run.

Haven't worked on a '66 yet only the 70's so this may not affect yours. When throttle shaft bushings wear out they are about berkeleying impossible to tune. Test the shaft/ bushing w/ propane to eliminate that possibility. Throw a rebuild kit in it if it checks ok, super easy rebuild. Don't trust all replacement carbs, some of them mfg. in Mexico are junk outta the box.

Most factory dizzys w/ vac advance are shot, most were replaced w/ mech advance models by owners. I had the best luck w/ aftermarket electronic dizzys. It's been a few years since I berkeleyed w/ these, I have this stuff bookmarked somewhere, will post later.

It has an almost new cheap generic replacement carb, and bosch 009 mechanical advance distributor. Yeah any info would be great, I have read a bit about how to set the idle already, but the idle doesnt change at all when you move the adjustment screws, and it doesnt even run at all with everything set where they say to start before you adjust everything.

Some of the later carbs had an electric idle fuel cut off valve to eliminate after running aka dieseling. If this it not working or not connected the engine won't idle.

Interesting, this one does have that and it's hooked up, idk if it works though, I haven't driven it much since it doesn't really run too well, but it does diesel sometimes.

air leak somewhere-----

Travis_K wrote: Interesting, this one does have that and it's hooked up, idk if it works though, I haven't driven it much since it doesn't really run too well, but it does diesel sometimes.

You can test if its working by having the engine off and then disconnect the wire going to it. Now with power on just touch the wire to the terminal and you should hear a click. No click, no worky.

As simple as the solex carbs are they have always been a bear to tune for me. Seems there is always something wonky with them preventing proper adjustment.

I'm probably going to replace the distributor with a vaccum advance one, and next time I look at it I will check again carefully for vaccum leaks and make sure the fuel shutoff solenoid works. If neither of those things are the problem, are there any other carbs that work better on a stock bug engine, maybe a weber or something?

Travis_K wrote: I'm probably going to replace the distributor with a vaccum advance one, and next time I look at it I will check again carefully for vaccum leaks and make sure the fuel shutoff solenoid works. If neither of those things are the problem, are there any other carbs that work better on a stock bug engine, maybe a weber or something?

On a stock motor a GOOD solex is your best bet. Most of the webers out there are progressive style and if you think getting it to run right on the solex is a pain the webers are much worse. Honestly if there are any aircooled gurus in your area its worth a few bux to let them take a look. I fully rebuilt the solex on my dad's bug and we spent a couple of months fiddling with it never quite getting it to run right. Finally gave in and took it to a recommended shop near him. They found a bent or loose tube in the carb, fixed it, cost about $40 and the thing runs like new.

Is a good solex a new generic replacement (what is on there now), or should I try to find an original one?

might wanna take a look at this:

http://www.hot-spark.com/Hot-Spark-SVDA034-3BOS4U1.htm

Will replace the 009 mechanical adv. w/ vacuum adv. and no points to berkeley with. Should be compatible w/ your carb, but check n e way. Test ignition coil too, I've found a cpl outta range, they're cheap too.

The thermal vac switch which opens the carb air preheat damper goes bad, you can test that w/ Mighty-Vac vac pump or similar to see if it holds, no replacement for that switch as I found and that will berkeley w/ tuning. You could have perfect idle/run at 70° but same day at 40° nights won't idle or run for E36 M3.

It turned out the problem was that the wire to the fuel shutoff solenoid got disconnected, so once I fixed that it runs fine. But, now fuel drips out of one of the casting plugs in the carb after it has been running a bit. The carb looks almost brand new too, I really hate badly made parts. Idk if it could be fixed or not, but a new carb is cheaper than a new bug, so it's getting replaced because I don't trust using it anymore.

If it is an external leak, but a good coat of your favorite epoxy over it. When the affected area is clean and dry... This used to be one of those tips you did when rebuilding a Quadrajet carb. YMMV, but what can it hurt to try?

^ what he said. It is probably the casting plug dead center as you face the carb. The one that is missing in this photo.

Common cause of engine fires because they all seem to start leaking at one point or another. An application of JB Weld or other fuel safe epoxy over the plug will make it good to go.

Yeah, it is that one. At least on a quadrajet it drips into the intake manifold, not down the outside of the carb. I don't really trust just covering the plug with epoxy though, its not worth risking losing the whole car if it ever leaked. I'm not sure what to replace it with though, it seem like bug carbs are hard to find unless its for a big engine with lots of work done to it.

Travis_K wrote: Yeah, it is that one. At least on a quadrajet it drips into the intake manifold, not down the outside of the carb. I don't really trust just covering the plug with epoxy though, its not worth risking losing the whole car if it ever leaked. I'm not sure what to replace it with though, it seem like bug carbs are hard to find unless its for a big engine with lots of work done to it.

No really the epoxy is the fix, it's been done on many cars and it holds. For a stock motor you dont have alot of other options. You could switch to some small duals or a small Dellorto 2 barrel like we used to use on solo vees (they still ran 1600s so you can tune one down for it) the progressive carbs are terrible to get tuned right.

But really there is nothing wrong with using a good epoxy on that plug.

Other option might be to thread it and put a pipe plug in it.... Other cause of engine fires was the pressed in fuel fitting coming loose at the fuel pump or carb. But that is a different story...