TheSamba.com :: View topic - Carb Questions 34 PICT-3

Wed Sep 25, 2019 9:44 pm

I have a '70 bug, stock 1600 dual port, old (35 yrs ?) 009 distributor. About 2 yrs ago, I got a cheapo stock type replacement carb off ebay. 34PICT-3. Have had flooding problems with it off & on.

Initially I thought it ran well, but SOMETIMES after it had been shutoff for 10 minutes or so, it wouldn't restart without holding the throttle wide open.

Other times when starting it cold, it will warm up fine on high idle and within 5 minutes or so as the choke comes off, it will start running rough and loading up. This seems to be more prevalent in the warm summer months.

I've replaced the needle/seat with genuine VW parts. Tried lowering the float level. Checked the fuel pump (genuine VW) pressure. But still these problems come and go.

Do I need to mess with the carb jetting ? I have no idea what sizes they are, let alone which/where they're located in the carb. Or could this be simply a matter of not tuning it properly. I must admit, this about the trickiest carb to tune in my experience, having an air/fuel mixture and a bypass adjustment as well. I tried to do it by the book. Sometimes it runs well, but not consistently well !

Any tips or advice is much appreciated....

Thu Sep 26, 2019 12:39 am

Sounds like maybe the carb is boiling over when you stop, flooding the engine. Not sure about the issues coming off fast idle. What do you mean by loading up?

Chris

Thu Sep 26, 2019 1:35 am

Loading up; I presume it's flooding. It won't idle and I have to pump it (throttle) to keep it running. Of course pumping it just compounds the problem. Black smoke coming out of the header each time.

It's a baja I use on our farm. Seldom do I even get it in second gear. It doesn't get used for any length of time, but being air cooled, I suppose it could be overheating a bit ?

With the carb that I replaced, it didn't have any of these symptoms I describe. I didn't realize until recently that it's actually undersized for the engine as it's a 30mm Weber. The accelerator pump was giving me problems (sticking) with it, so I replaced it with the 34 PICT-3. Definitely has more power with the 34 !

Thu Sep 26, 2019 6:28 am

If it doesn't leave first gear very often why change to the 34 PICT? That carburetor combined with an older 009 that likely needs some service is inviting running issues.

Thu Sep 26, 2019 9:31 am

It might be dirt round the idle jet - when the choke comes off it would lean out and die. Then you pump it full of fuel and it goes too rich ..
Either that or the electric shutoff valve is jammed or missing.

I would strip it down and blast it through with carb cleaner.

Thu Sep 26, 2019 10:45 am

In the owner’s manual, it states to hold the throttle wide open during a hot restart. FYI

Thu Sep 26, 2019 3:51 pm

Interesting. Is normal operating temperature considered hot ?

tasb wrote: If it doesn't leave first gear very often why change to the 34 PICT? That carburetor combined with an older 009 that likely needs some service is inviting running issues.

As mentioned, the 30mm Weber had accelerator pump problems. Got tired of messing with it and couldn't resist the $50 ebay special for a new 34 ! :oops:

The centrifugal advance on the distributor seems to work properly. I've kept it oiled over the years. Very low mileage (hours on a farm vehicle) also.

Thu Sep 26, 2019 4:05 pm

mikedjames wrote: It might be dirt round the idle jet - when the choke comes off it would lean out and die. Then you pump it full of fuel and it goes too rich ..
Either that or the electric shutoff valve is jammed or missing.

I would strip it down and blast it through with carb cleaner.

I've bench tested it- just have it setting level and fill up the float bowl through the inlet. Didn't show any sign of leakage.

I'll dig into it deeper and see what I find....

Thanks for everybody's reply.

Thu Sep 26, 2019 6:34 pm

Sorry I wasn’t more clear. When I said “hot”, I meant operating temp, or already warmed up.

Now, having said that, if you are experiencing richness at times, then you might have a flooding issue. But I remember when my engine was completely stock (1600 DP, 34 PICT 3 and 034 distributor), I would have to put the throttle to the floor on a hot restart, such as running into a store and restarting 15 minutes after being parked.

Thu Sep 26, 2019 8:27 pm

I always hold the gas pedal to the floor to start the car. This is the recommended starting procedure.

Thu Sep 26, 2019 9:52 pm

OK, thanks guys, I can live with that.

So this is the other problem. Has happened about 4-5 times in the last 2yrs.

Garfields Bug wrote:
Other times when starting it cold, it will warm up fine on high idle and within 5 minutes or so as the choke comes off, it will start running rough and loading up. This seems to be more prevalent in the warm summer months.

As mentioned, it's an intermittent problem. I have the carb off now and will disassemble and blow things out. I have a diagram with parts breakdown of a 34 PICT-3. I see the main jet, "air correction jet" and a "pilot jet" on the right side. Looks like the pilot jet screws in on the outside of the carb ? Is that the idle jet ?

EDIT; nevermind, I found a couple schematic diagrams in the forums here. Answers my questions for now....Thanks !

Fri Sep 27, 2019 4:22 pm

Also, don’t forget, the choke may require seasonal adjustments.