Has anyone ever replaced a 914 Turbo?

This is a constant problem with my older 914. Lubricant of waste gate is necessary.

1. In pre-flight turn on power long enough for the wastegate servo to move to full cable slack.

2. Manually verify that the wastegate is free moving.

3. If free moving fine, otherwise apply a small amount of MouseMilk and work the mechanism until freely moved and will return with the spring force.

4. On every pre-flight run up, slowly go to full power while observing the manifold pressure. A sticking wastegate will over boost. If this the case perform steps #1-#3.

In your case boost pressure increased up to 58 Inch, but Rpm doesn't go beyond 5750. That is little bit tricky. As 58 Inch boost pressure, RPM should go beyond 6100.

I suggest check airbox pressure sensors and 3 way solenoid vavle?

Check servomotor operations function?

Lubricates waste gate pin  for ease movement.

{Stay at Home, don't Call mechanic}

We will help you. ?✈️???

Unless you intend on spending $5000 every time the Waste Gate sticks, I would make a real effort to free up the one you have.

Flood the moving parts with motor Oil and cycle them a zillion times until they move smoothly.

Then wash the bearing sleeve with kerosene or brake cleaner to remove all the Oil.

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I am tempted to make a humorous comment about using Muffler Bearing Grease here. But I won't.  

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Your video does not show the action to be very bad.

That little stickiness doe not look like it could hold that valve closed.

The cable holds the Waist Gate in the closed position while the spring and more importantly the exhaust gasses and engine vibration are trying to Open it. it is designed to fail OPEN.

I would suspect a binding cable or an intermittent servo is the real problem.