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Thu Feb 02, 2006 8:52 am

(I posted this to the Ghia forum, but I'm tossing it up here too in case there's more helpful traffic)

I just put a new 34 pict 3 carb on my '68 Ghia and I'm having some trouble getting it to idle. (The old carb was replaced because thar car had been sitting for a while and I opted to replace the leaky carb instead of a rebuilding it.)

I can get the car to start, but it stalls after a few seconds unless I *really* mess with the accelerator. Typically, the engine fires up, the RPM's shoot up and stay there for a couple seconds before dropping and stalling. The other night, I eventually got it to idle on it's own as long as I held the choke closed and kept the RPMS high. As soon as I would let the choke open up (even a little), the engine stalled.

Since I can get the car to stay running, I don't think there's a fuel or spark problem. It seems to me more like an adjustment on the carb. Does anyone have any suggestions as to what could be causing this? Or maybe the fuel lines are clogged up, and it's not getting enough gas? I'm going to try some new gas next (since the stuff that's in there is old) and see what happens.

Thanks for any advice

Thu Feb 02, 2006 9:22 am

Does it have the electric idle cut-off on the side of carb, that needs to be hooked up as well but it sounds like it is starving for fuel, check fuel lines and fuel pump too..............good luck

Thu Feb 02, 2006 9:34 am

Cut-off is installed and functioning.

Thu Feb 02, 2006 9:44 am

not_so_furious wrote: (I posted The other night, I eventually got it to idle on it's own as long as I held the choke closed and kept the RPMS high. As soon as I would let the choke open up (even a little), the engine stalled.

Sounds to me like a MAJOR vacuum leak somewhere, too lean. Gaskets good?

Did you disassemble and clean the carb you just put on there?

Thu Feb 02, 2006 11:06 am

Which gaskets are you questioning? When I had things torn apart over the past couple months I replaced: intake to cylinder head gasket, preheater tube gaskets, rubber boots on the manifold, carb to intake gasket.

I didn't disassemble my new carb. A vacuum leak is interesting. On my new carb there was an extra vacuum-looking connector on the rear. I plugged it since I wasn't using it. I haven't seen any description about what this is for.

Also, my old carb had a couple screws plugging ports on the rear of the carb, but I also haven't found a description for what those ports are for. I can take a picture tonight if you're curious. I didn't plug them on my new carb, because they didn't look like they were used for vacuum, plus the holes weren't threaded and I didn't want to jam a screw in there unless I knew I needed to.

Thu Feb 02, 2006 11:32 am

Yes, pictures would help greatly.

What did your OLD carb do? Which gaskets did you use at the head/manifold connection? The metal ones?

Thu Feb 02, 2006 12:22 pm

Did you look in the gas tank? There might be a pile of rust covering the outlet and starving the carb. Good luck. Oh ya. Check under the tank also. Maybe PO placed fuel filter there and it is clogged full, or fuel line is kinked or pinched.

Thu Feb 02, 2006 1:19 pm

I tried for a little while to run the car with the old carb, but after I saw it dripping gas all over my newly cleaned engine parts I decided to replace it. I suppose I could try putting it back on briefly to see how well the car runs. I used the metal gaskets at the head/manifold.

The fuel isn't completely blocked because the car runs, and I can also see the fuel filter full of gas. (I've got one of those clear ones.) If the flow was being restricted I would expect to see the filter emptying out quicker than the pump can pull more fuel in. I'll hop under that car and take a close look at the fuel path.

Thu Feb 02, 2006 1:36 pm

Did you remove the manifolds more than once while using the metal gaskets? I've never had any luck with the metal ones. I prefer the big thick grey fiber ones.

I don't think that's the root of your problem though, but you never know. Do you have any propane or ether you could shoot at the base of the manifolds, to test for vacuum leak? Be careful.

Are you sure the inside of the carb is nice and clean? If you've never taken one apart, it's REALLY not a big deal. Here's how.

http://www.vw-resource.com/carb_41.html

Thu Feb 02, 2006 3:20 pm

I've taken a carb apart before. The only reason I haven't opened my new one up is that they have the screws marked so they know if it's been opened. In the event that the thing is crap, I don't want them denying my return because I've voided the warranty.

I don't have any propane, but could I spray some starter fluid or carb cleaner in that area instead?

Thu Feb 02, 2006 7:43 pm

Here's a picture of my old carb with 3 questionable ports circled:

And the new carb:

You can see that I plugged one of the circled ports, since it had a tube coming out of it that was easilly capped. I left one of the others alone, and the third one doesn't exist on the new carb.

Do you know what those are for?

I'm off to the garage now to play.

Thu Feb 02, 2006 9:09 pm

Just got back from the garage. I double checked the points. Then I hooked up a gas can to the fuel pump. It maybe ran better, but only marginally. I still had to hold the choke all the way closed. Even after running it for over 10 minutes, it would still run poorly (and eventually stall) if I opened the choke. I could get it to keep running, however, by continually blipping the throttle while the choke was more open. I forgot to check make sure the intake was firmly bolted on to the cylinder, and now the engine is quite warm and I'm out of time. I'll have to check that another time. I also didn't check the valves due to time, but I don't really see how it would be contributing to the problem.

So this experiment ruled out the fuel supply as my source of trouble. Any other ideas based on what I've seen so far?

Fri Feb 03, 2006 7:27 am

I don't see anything wrong with the ports on the carb, it should run.

Have you went through the adjustment procedures? How does it react?

http://www.vw-resource.com/34pict3.html

Fri Feb 03, 2006 8:27 am

From that page:
Valves - not adjusted. Don't think it matters (but I still plan on doing it after I grab some new gaskets, just in case)
Points - done
Timing - need the car running and warmed up. I can maybe do this if I rig something to hold the choke closed.
Choke - Adjusted, but irrelevant because I'm holding it closed.
Carb -
I was kind of working on the assumption that the carb would be set up relatively close out of the box. I did adjust the volume screw, but I have not touched the bypass. I also did a quick adjustment of the fast idle screw.

It's unlclear to me what the bypass and volume adjustments do to the fuel mixture. Since I can only run the car with the choke closed, it seems like the problem is a lean mixture, right? Would one of the carb adjustments richen up the mixture? Maybe I can mess with those two adjustments while the car is running and see what happens. How would I know if it is richening up the mixture?

Are there any VW mechanics that make house calls? :)

Fri Feb 03, 2006 8:31 am

Another thing I noticed too (and this is probably unrelated), the left side of the engine bay was quite a bit warmer than the right side. I had a hard time holding my hand on the meal surrounding the engine on the left side, but it felt much cooler on the right side. Is that normal?

Fri Feb 03, 2006 9:01 am

not_so_furious wrote:
Valves - not adjusted. Don't think it matters (but I still plan on doing it after I grab some new gaskets, just in case)
It DOES matter a lot, since it's an unknown variable to you.

not_so_furious wrote:
Timing - need the car running and warmed up. I can maybe do this if I rig something to hold the choke closed.
You ought to be able to static time it to get it in the ballpark.

not_so_furious wrote: Carb -
I was kind of working on the assumption that the carb would be set up relatively close out of the box. I did adjust the volume screw, but I have not touched the bypass. I also did a quick adjustment of the fast idle screw.
Don't even assume the carbs are usable out-of-the-box. Often they're jetted incorrectly for your engine, missing parts, poor fit, etc. Have them checked by someone before going any further.

Fri Feb 03, 2006 11:19 am

Mark wrote:
It DOES matter a lot, since it's an unknown variable to you.

It's not completely unknown. At one point the car was a daily driver, and I drove it into the garage where it now sits. But I do plan on double checking that anyways to rule it out.

Mark wrote:
You ought to be able to static time it to get it in the ballpark.

Where should I time it? 5-8 BTDC?

Mark wrote:
Don't even assume the carbs are usable out-of-the-box. Often they're jetted incorrectly for your engine, missing parts, poor fit, etc. Have them checked by someone before going any further.
Good point, assuming is a really dumb idea. I'm not really sure where I can take it to have it checked out. I could open it up myself, but I have no idea what I'd be looking for.

Fri Feb 03, 2006 11:48 am

Your timing will determined by what distributor you are running. Does the distributor have a vacuum canister and hose connected to it or not?
If it's a 009, then I'm sure others will quickly chime in here :?

Fri Feb 03, 2006 3:30 pm

It's an 009. I know, but I'm not replacing it with and SVDA until I get the thing driveable. :)

Fri Feb 03, 2006 5:01 pm

Your carb is running very lean -- that's why you have to hold the choke closed to keep it running. You have some major work to do with the two adjusting screws. Do you have a good procedure? If not, please see -

http://www.vw-resource.com/34pict3.html

Good luck!