thanks for the ideas. i think the choke, needle, timing (static, 7,5 btdc with svda distributor), accelerator pump/pipe are ok. I rerouted the fuel line and covered it with aluminium tape. it’s a good idea smelling the pipes.
I also checked the fan belt and could press it in almost an inch, maybe too much, it could have slipped a bit, causing some overheating, another idea.
71 and 72’s are the only years VW separated the fuel shut off valve from the pump. These two years had a factory installed mechanical in line fuel shut off valve located right next to the pump. If someone took this valve off, the left over fuel pressure in the line between the pump and carb is slowly pushing through the card and flooding the engine after shut off.
If the engine starts up right away after being shut off…
If the engine starts up until a minute or 3 after shut off…
If you must hold the accelerator to the floor and crank for 15 + seconds to start when the engine is warm…
Your engine is flooding when hot and if the pump is original but missing the cut off valve you only have a couple of choices before you go Macgyver on it.
Solution - Find a cut off valve. (GOOD LUCK!)
OR…Use an earlier or later pump depending on if you have an alternator or generator.*** Beware if you change pumps, you may have to replace or adjust the length of the push rod that moves the pump arm. The crook neck pump uses a shorter push rod 100mm (alternator type) Generator rod is 110mm. Get new or grind the rod you have if needed. Get extra gaskets and adjust pump pressure to 3-5psi at 3500-4000 by reducing how far the rod can push up by adding more or less gaskets under the black plastic spacer under the pump (on top probably works as well). Mine is 2.7-3.6 depending on RPM. Good Luck!
You should realize this thread is in the ancient history category.
That being said, I’m curious about this fuel shut off valve you mention. There is a shut off solenoid on the carburetor that is electrically operated and could be prone to problems.
How about a link or some kind of verification this creature even exists.
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