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Sun Sep 07, 2008 8:06 am

Hi, recently had problems with the Solex pdsit 34 twin carbs on my 2.0 litre cu engine. The word I got back from my mechanic was "you need new carbs mate". The report he gave me states:
No CO% L/H carb, unable to adjust, shut off valve not working. Possible metal paste to carb top.
NO CO% O/S carb, unable to adjust. No balance between carbs, O/S accelerator jet missing.
erratic idle and HC high.

I'm no mechanic, can anyone tell me if this is a new carb job or if it can be fixed? If anyone could explain this a little better to me than the mechanic did (who I was not impressed with and won't be using again, but that's another story), I'd really appreciate that too.

Sun Sep 07, 2008 9:53 am

It's been quite a few years since I've dealt with the 34 PDSIT carbs, and some of what the mechanic has written is not really clear to me. What it sounds like is that the idle cut-out solenoid may be dead or gummed up. Those are easy to take out and check the solenoid operation: apply +12v to the electrical connection, -12v to the housing, and it should pull the little plunger back. If the plunger is bent or has any build up on it, though, it may be hanging up in the bore.

A common problem with those carbs is that the throttle shaft bore will wear and then it won't operate properly. If you disconnect the linkage from the carbs and then try moving the shaft side to side and up and down, you may be able to see if they are worn. It doesn't take much wear to make the carb pretty much impossible to set up right. I don't know what it would cost to have those carbs rebushed... I did mine myself with a drill press, some clamps, a machinists' reamer, and bronze bushings I bought at a local home improvement store. It was a pretty "shadetree mechanic" rig that worked beautifully, but it doesn't sound like you're set up for that. If I'd paid someone for the time I put in it would have been cheaper to buy new carbs.

Other than that... carbs usually benefit from a tear down, clean everything, and reassemble with new gaskets and float needle valve if they've been in service for awhile. If you can find a good mechanic that could strip the fuel injection from a donor engine and install that you may be better off. There may also be some replacement carbs available... Weber used to make some that were almost identical in bore and jetting but I think they're discontinued; 34 ICT comes to mind as the Weber model.

Mon Sep 08, 2008 9:10 am

Thanks for your help. I've purchased a pair of PDSIT carbs from e-bay yesterday which I hope to be able to use as donors or replacements. Anyone know where I might get a PDSIT refurb kit?

Mon Sep 08, 2008 9:23 am

I'm not sure about the carb rebuild kit... I would just check the VW parts vendors. I thought about the earlier post and wanted to suggest that you cross-post on the Bay Window Bus forum if you haven't already. In the U.S. carbs were used only on the early 1.7/1.8 liter engines, which are basically the same as your 2.0 liter. After that I think everything was FI, including the early Vanagons. You may find someone with more current experience with those carbs on that forum.