912 changes sound after electrical pump on

by Przemysław Wiśniewski in 912 / 914 Technical Questions 10 years ago

Hi. Last time I found that when I turn on electrical aux pump my engine changes a little bit sound. It's sounds like a few rpm down after pump on.
It's normal?
My fuel flow - finally installed after vapor lock valve shows me about 1lph more on electrical pump.
Pump is oryginal installed by comco ikarus.

It is normal?

Re: 912 changes sound after electrical pump on

by Rob Seaton » 10 years ago

Rob Seaton

3 1.32k 251

Can you hum a few bars? :lol:
No, it is not normal.
-Does the EGT drop? Maybe the float valves are being forced open by too much pressure? what is the pressure rating of the aux pump? It should not be more than 4.4psi.
-Does your aux pump have a electrical problem and cause a high amp load? That would load up the generator and cause the engine sound to change.

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Re: 912 changes sound after electrical pump on

by Przemysław Wiśniewski » 10 years ago

Przemysław Wiśniewski

65 247 3

Hi, there are no electrical problems. Volage is constans, breaker is 5A.
I don't know pressure of pump - it's oryginal comco ikarus pump - maybe I'll find any label.
I havent egt sensors. I'll check it during the flight on high rpm..

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