914 overboost

Re: 914 overboost

by Rob Seaton » 11 years ago

Rob Seaton

3 1.32k 251

Hi Greg,
Sounds like your wastegate is stuck in the closed position.
Cycle the master switch and watch the wastegate at the same time; it should open and then close again.
If you use avgas it is likely the lead has caused the stickiness. You can use mousemilk, AeroKroil or even brake-clean to free up the shaft. Then lubricate it with a small amount of high temp anti-seize.

Re: 914 overboost

by Greg Regan » 11 years ago

Greg Regan

25 75 31

Thanks Rob
The waste gate seems to cycle OK Is there anything that can come adrift inside the unit to make the gate stay shut
Greg

Re: 914 overboost

by Rob Seaton » 11 years ago

Rob Seaton

3 1.32k 251

Is the cable OK?
you may have to take off the muffler and inspect the valve assy.

Re: 914 overboost

by Greg Regan » 11 years ago

Greg Regan

25 75 31

The cable looks OK looks like a nightmare to remove the muffler so it is possible for the valve to become stuck shut.

Re: 914 overboost

by Rob Seaton » 11 years ago

Rob Seaton

3 1.32k 251

If you turn the master ON for a few moments and then shut it off the wastegate should be in the open position. You can then wiggle it open an closed to see and hear if it is OK.
Note: Very old 914's has a pivoting wastegate poppet valve that could get stuck in the closed position. All new engines starting around 1999 have a welded poppet valve.