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Discussion Starter · #1 · (Edited)
Hi Volkszone community! I recently bought a '73 Beetle and rejoiced in a few lovely drives, but the honeymoon period has come to an abrupt halt, as the little blighter is refusing to start. I'm hoping somebody may be able to help with some advice. Here are the symptoms:

  • The engine is cranking well on the ignition but it's not starting, so I assume it's a case of either no spark or no fuel.
  • There is the usual plastic aftermarket fuel filter in the engine bay (I will move this soon to reduce the fire risk, but just need to get the car started for now. NB: It's in the inadvisable position between the fuel pump and the carb). It only has a tiny amount of fuel at the bottom of the filter. Should this have more than a drop of fuel in it?
  • When somebody cranks the engine, I can see the fuel moving in the filter, but the filter is not filling up. Should the pump be filling this with petrol? I'm wondering if there is a blockage in the fuel line and the pump is just moving air in the filter at the moment?
  • I need to reverse up a steep drive to park the car, which might have sent debris down the fuel line, I suppose.

My next steps are:
  • Remove the pipe between the fuel pump and the tank and see if any fuel comes out.
  • If not, try and blow air down this pipe to the fuel tank to try and shift any blockage. Should I be able to hear bubbling in the fuel tank when doing this?
  • Reconnect the pipe between the fuel pump and the tank. Disconnect the pipe out of the pump.
  • Crank the engine by hand to see if the pump is pulling through fuel.
  • Replace the filter for good measure.

The car had been stood for a long time so I guess the ethanol in the fuel may have eroded parts in the pump., or somewhere else in the fuel line?

That's about all I can think of for now, but if anyone has any advice, pointers, suggestions or anything that might be of use, I would be enormously grateful. The engine is a 1600 single port with a standard Solex 34 PICT carb with oil bath filter, as far as I'm aware.
 

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You seem to be concentrating on fuel when by far the most common cause of dead cranking is no spark. As a quick test pour a few cc of fresh fuel into the carb. It will fire up almost instantly and run for a second or two if you have a spark.
 

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Welcome to VZI.
I agree with Beetlebank, test for a good spark before tearing the fuel system to bits.
It is not unusual for those plastic fuel filters to appear to contain more air than fuel, (they seem to hold a 'bubble').
 

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Discussion Starter · #6 ·
Success! Not quite sure what swung it, but this is what I did:
  • Replaced the fuel line before the pump and added a filter here (there wasn't one on the inlet side of the pump before).
  • Checked that the pump was pulling through fuel (it was).
  • Replaced the fuel line between the pump and the carb, and removed the filter here.
(The car wasn't starting at that point)
  • Took off the air filter and poured a small amount of fuel into the carb bowl while the car was being cranked.
At that point, it sprang into life. I ran it for over 5 mins, and it then stopped and started on the key several times.

Above all, I'm glad it's now working, but I'd love to figure out where the problem lay. As it subsequently started on the key wihout fuel being added to the bowl, does that suggest that the problem was probably a fuel blockage somewhere and not spark?
 

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Glad to hear it's running. It sounds like the pump might not functioning as it should as it would nut run 5 minutes on a float bowl of fuel, so it must be working after a fashion but perhaps not at full flow. The genuine pump in my Bay is like this - runs perfectly but takes an age to prime the twin 36DRLAs from empty. I have never bothered to replace or investigate it further. A blockage on the fuel side is possible but rare, however it is worth checking for correct operation of the needle valve/float.
 

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Discussion Starter · #8 ·
Thank you - I much appreciate it! I'll keep a close eye on it and try to give the car some decent run-outs over the next few days and weeks. Next steps for me are to replace the old, cloth-covered fuel line at the tank end, as that doesn't look too confidence-inspiring, and tighten up the pulley belt, which is flapping all over the place.
 
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