RPM drop with a 914 above 100%

Re: RPM drop with a 914 above 100%

by Carlos Chazarra » 13 years ago

Carlos Chazarra

0 8 0

Hi all,
I replaced carburettor gaskets and... It seems issue ended!
Well, I obtain more powerful, 35 MAP and 5000 RPM, stable power, without fail, and I am happy now.
I don't know if this is normal, or is still too low. I don' t reach 5500 in the airfield, perhaps in flight ??
Roger, may I obtain 5500 or 5000 is ok?
Thanks, I will confirm finally after some hours engine tested.

Re: RPM drop with a 914 above 100%

by Roger Lee » 13 years ago

Roger Lee

131 5.38k 5.44k

Hi Carlos,

Do you have an in flight adjustable prop?

5000 would be okay for a static, but way too low in the air for a max rpm. Go fly it first and see what rpm you get at WOT.

---

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Re: RPM drop with a 914 above 100%

by Carlos Chazarra » 12 years ago

Carlos Chazarra

0 8 0

Anybody can confirm to me if turbo must Work when static test is done or no ?
I don't see turbo lights ON and that thrust as well (5000 rpm and 38 "MAP),
Is possible it has any sensor to just work on flight?

Re: RPM drop with a 914 above 100%

by lasek jerome » 12 years ago

lasek jerome

4 8 0

Hi Everybody,

I am a friend of Jerome and have similar problems as Carlos on my 914.
The 914 here is fitted on a Europa aircraft.
The only difference with Carlos is that engine failure is erratic and does not occurs everytime.

First time I was at FL 130 during climb with 32'' Hg of manifold pressure. Suddenly there were some drops of power and indicator of mannifold pressure made loops between 28 and 32'' Hg.

After reducing power I could make a safe descent back to my base airfield, as the problem had disappeared with lower powers.
Then I made a local flight without any trouble. The next flight the failure occured during full power at take off. I could make a safe landing.
After a ground engine testing I realized the problem was appearing only after a small lapse of time
of full power setting.
During the first minute full power and 5600 rpm are reached normally. After this delay power becomes unstable and Manifold Pressure begins to oscillate. When applicating a small reduction of power the problem disappears....

The fuel system has been integraly checked, like for Carlos no warning lights flashed and fuel pressure is correct. The fuel regulator was rehauled with a new membrane (not expensive), carbs seems not to be involved as there are NO vibrations during the phenomenum.

I have to check the waste gate cable tightening, but the operation of waste gate appears normal when displacing the throttle along its course....

Thanks for your comments & reactions

FG

Re: RPM drop with a 914 above 100%

by Greg Regan » 12 years ago

Greg Regan

25 75 31

Had a similar problem with my 914 , no power after going above 100% tried everything seemed worse after using avgas ended up changing the fuel pressure reg and it came good but still have trouble if I have to use avgas until the avgas gets watered down with mogas