My son and I have been struggling to get his 73 914 1.7 back on the road. So far we have gone through the fuel system: cleaning the fuel tank, replacing the fuel pump, new fuel lines. We have had the webers rebuilt. We have replaced the throttle linkage.
The engine will turn over and occasionally start for us, but will not idle smoothly. Recently the car will start and idle rough and then will suddenly shut down and make a sound as if something is binding! Our frustration is rising and would like to ask for any advice that others with more experience with type 4 engines may have.

Thanks in advance.

Check the basics first.

- Do you have spark? You can grab an extra spark plug and hook it to a plug wire. Tape it so the outer electrode (or the threads) are touching a ground, and watch while someone cranks the starter. Sparks should be visible in the gap. Also double-check that your plug wires are connected correctly. The firing order is 1-4-3-2, which is noted on embossed letters on the engine tin (look for "Zundfolge"), and the cylinder numbers are also embossed on the engine tin near the spark plug holes.

- Do you have fuel? Is fuel getting into the float bowls of the carburetors? Do you see fuel squirting out of the accelerator jets when you open the throttles? Do you smell fuel at the tailpipe after cranking the starter for a while?

- Do you have compression? Does the starter motor crank evenly, or is the sound uneven? An uneven sound may indicate a cylinder with no compression. A compression gauge will tell you for sure, though.

With those three things, the engine should run, if the amount of fuel is somewhere close and the spark timing is somewhere vaguely in the right area.

You can do a "static timing" setup so that the spark is happening right around TDC, which should be enough for the motor to run. As for the fuel amount.... Well, I don't speak carburetor, so I'm out of suggestions for that. Make sure you don't have any vacuum leaks, and then... ??

--DD

If it sounds like binding I bet your timing is way off. Have you located the timing mark and verified your plug wires are ordered correctly?

Not enough info to be of much help.

You mention idle problems. What size are the Webers? Are these 40 IDF or 44s? 44s are not likely to ever run well on a 1.7L.

What size venturis? Sounds like someone else rebuilt the carbs? Did they set the float level?

Have you airflow balanced the carbs barrel to barrel? Are carbs synchronized carb to carb? Have you set idle mixture?