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My 914 has developed a small hesitation when accelerating to full power at around 100% throttle position. It doesn’t do it every time but often enough to be concerned.

Another thing that seemed to happen at the same time was that during startup the TCU/ servo cycles as normal but then  sometimes appears to want to begin cycling again but only moves a very small amount and does this 6 or 7 times.

I have no idea if the two problems are related but would be keen to know if anyone has any ideas. I could start replacing various items TCU etc this would however be an expensive way to problem solve.

Again , I’m not sure if a problem I had on a recent X country trip may also be a piece of the puzzle. While away on a three week trip around Oz the engine suffered an intermittent problem where I could only get 35” of manifold pressure on takeoff which made for some pretty sketchy experiences. That problem seems to have fixed itself as it has not happened again in the past 50 flight hours.

Any help would be appreciated.

  • Re: 914 turbo

    by » 4 years ago


    Rick,

    I am by no means an expert, but I’ve learned a lot about my 914 in a year of owning it.

    1. Check the wastegate actuation on preflight. It can coke up and not move; some mouse milk squirted up in there will loosen it on up.

    2. Verify the airbox is connected to the carbs. Mine rattled loose (lots of problems led to that) but it prevented the turbo from delivering full boosted pressure to the carburetors (I think 31” is sea level pressure, so 35” is just a slight boost over ambient).

    3. Check the pneumatic synchronization on the carbs. When I reinstalled mine after refurbishing them I didn’t do this properly at first and full throttle in the cockpit wasn’t full throttle on both carbs. 

    4. Check that both electronic ignition modules are working. I had a P-lead broken on the B module and a contaminated 2/4 carb (led to point 3, above), so basically only the top half of my 1/3 cylinders were functioning properly. 

    Again, I’m not an expert and you probably don’t have my problems, but if you check them you can rule out these specific issues..

    Gold luck!

    Sean


    Thank you said by: RotaxOwner Admin

  • Re: 914 turbo

    by » 4 years ago


    Thanks Sean, the wastegate works and is coke free. I did have a loose carburettor connection to the air box which has now been fixed. I swapped the servo off another machine and the first TestFlight has been successful, hopefully it is now fixed.


    Thank you said by: RotaxOwner Admin

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