1972 PDSIT no start

[amikulics]

I have a 1972 bus with a 1700 type 4. A few months ago I cleaned up the engine and installed new ignition parts, at the time the engine had a progressive Weber carb. It ran and drove like this pretty well but I wanted to keep it original so I cleaned up and replaced all the gaskets on both factory dual carbs. I cannot get it to start now, I believe the timing and ignition is all still set correctly because it will start for a second after spraying carb cleaner down the intake. My main problem is that all the set up information I’ve found relies on the engine already being able to idle. How can I get the engine to idle?

[Tcash]

If it runs on carb cleaner, you have a fuel delivery problem
Fuel pump, clogged fuel filter or tank.
Good luck
Tcash

[busdaddy]

Are all 3 solenoids clicking when you connect them to the coil? (key on), do you see any fuel squirt or dribble down the throats when you open the throttles quickly?
Disconnect the green wire from the coil if you are going to be experimenting more than a few minutes.
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[amikulics]

One of the solenoid wires was very corroded so I replaced all of them today. It starts and the RPMs get very fast then it dies. And to answer your other question: yes, fuel squirts out when the throttle is moved.

[The Fez]

[busdaddy]

[amikulics]

I decided to look for large vacuum leaks and I found that plugging the brake booster hose will allow the engine to start. I actually did this a day or two ago and the engine would start and idle for few seconds before racing up to 3000 rpm, so I adjusted the chokes to be a little more open, this seemed to fix the problem but I only quickly tested it.
Today I tried it again and at first it was idling rough at around 650 rpm and opening the throttle seemed to make it run worse. I also tried turning the idle speed screw a half a turn at a time but it didn't seem to affect it. But after a few starts and stops the engine continued its previous problem of starting and racing to 3000 rpm.

[busdaddy]

Sounds like you are making progress, did you set the float levels, choke linkage and throttle gaps as described in your Bently manual?, have you rebushed the throttle shafts?

Have a look at this: https://www.thesamba.com/vw/forum/viewtopic.php?t=399195
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[amikulics]

I set everything as the manual described. I gave it another shot today following the post you linked, he said to ignore bentleys adjustment of the throttle plates and I tried his method of adjusting the plates with no luck, so my throttle plates may be out of exact adjustment. The engine still wants to idle way too high (~3000 rpm); a few times, for a few seconds, it would idle better on start up (~700 rpm) but it would run really rough. I'm still completely lost as to why it wants to rev so high. I tried adjusting the central idling screw, and the volume control screws on each carburetor but with no luck. I have the proper tool to do the synchronization but it's revving way too high to be able to try it. Any help would be much appreciated.

[busdaddy]

There must be a hose off or other vacum leak you haven't found yet. How about some pictures of your engine?, maybe we can see something you don't.

https://www.thesamba.com/vw/forum/viewtopic.php?t=6
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[amikulics]

Here's some pictures of the engine:

[Wildthings]

Your chokes are set (or wired) so that they are open all the time. That is going to keep it for running well cold and could be part of your problem. You could set the chokes so the butterflies are just closing with the engine cold and then see if it will start and keep running.

[Westfalia73]

I have a 73 running the factory PDSIT carbs, I didn’t realise that between 72 with the oil bath air cleaner and 73 with the paper element there was a bit of difference because my set up is different to yours in many ways.....you seem to have a different throttle lever that is missing the tab for the return spring (I just knocked up one my spares to take these pictures)..

Mine has the tab where the return spring connects to the choke cover ring which you seem to be missing as well....

You also seem to be missing the dash pot...

Fully assembled it should sort of look this this...

Again yours maybe should be like that but I’m not sure of the ringed screws in the tinware for the return spring?
I have had the same issue as you in the past where when I started it it would just rev its arse off full speed, no amount of dicking around with the screws will fix this, I removed both carbs and followed the set up procedure by the book, starting with this... this is critical....

Once you have set up by the book you will have some great working carbs with plenty of power, I can’t stress enough how critical the complete set up is, follow it step by step and fingers crossed you can nail it... good luck
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1973 tintop westfalia weekender.
1973 beetle.
1981 Brazilian baywindow kombi.

[busdaddy]

The return springs on the carbs are a 73+ thing, 72 only (shorter manifolds) has a longer spring connected to a hole in the cylinder tin.
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[amikulics]

After going through all the advice posted here, I was able to get the idle down and now its idling pretty well (still a little high). I am having trouble getting them synchronized though, every guide says to just use the sychrometer to measure the air flow then just use the nut to adjust. I think I did this correctly but I'm not sure. Also it takes a long time for the engine to return to idle; I'm going to link to two videos one showing the synchrometer and timing, and another showing the delay returning to idle. Am I using the synchometer correctly and is it too long back to idle? Any other help or advice/suggestions would also be greatly appreciated even if it doesn't pertain to my two questions.

https://youtu.be/8eLNzd88lVQ

https://youtu.be/HNtaS5iQe-Y

[Wildthings]

Your valves sound like they are way too loose. If you have adjusted them recently and they are still making this much racket, maybe pull the rocker arms on the noisiest side to check that your valve stems aren't worn concave as this will throw the adjustment way off.

[amikulics]

I'm still having trouble getting these carbs properly synced. As you can see in the video they are close to where they need to be; but at ~1100 rpm my synchrometer is almost maxed out. I know that I'm supposed to sync at ~2500 then re-sync at idle but how can I sync them is the scale is maxed out so early? Most of the guides I've seen use the uni-syn style gauge but I only have the snail style. Any help or guides would be much appreciated.

[Abscate]

A good synchronizer will have a bypass hole you can open at revs to accommodate the higher flow and keep it on scale.

You can drill one in a cheapie
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[amikulics]

Today I was able to get almost everything adjusted, following ratwells guides. I am stuck on balancing he mixture of each carburetor. Both Bentley and Ratwell suggest starting both screws 2.5 turns out then disconnect the pilot cutoff and note the rpm drop. Disconnecting the left pilot cutoff drops the rpm to about 600 but no matter how much I tried to adjust the screws disconnecting the cutoff on the right always kills the engine. Should I continue to back out the screw on the right? or will both screws need to be adjusted to correct this?

[busdaddy]

When you disconnect the cutoff on the right and it dies or idles lower it's the left carb that you need to mess with, disconnecting a carbs cutoff cuts it off and takes it out of the picture.
Put the right carb back to the starting point and turn the throttle stop on the left carb in a turn (or more if it still won't stay running), then move on to the reference hose method to determine if it's rich or lean. Once that's close back out the stop screw to reach that 600 rpm the other carb gives and proceed with fine mixture and speed adjustments.

To summarize: disconnecting a cutoff on one carb is a test for the opposing carb.
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