mixture issue

[Aaron Lachman]

i noticed on my last flight , i had to fully enrich the mixture to keep TIT in optimal , the higher i flew the more i noticed i had to enrich, any ideas what could be causing it

[N201MKTurbo]

It would help to know what plane you are flying.

[jlunseth]

Also would help to know your power setting (MP, RPM and fuel flow), and what the TITs actually were.  

[Raptor05121]

Welcome to the forums, Aaron.

Please post some basic details (model, engine, prop, etc, etc), also do you have an engine monitor and can back up trends, or has it suddenly started doing this?

 

[Aaron Lachman]

thank you guys in advance , i’m flying a m20k 252 tse with the rocket conversion , my usual power setting is 31 MP , 2300rpm , burning 18gph , mixture knob back one inch 10k ft .tit hottest cyl 1540 f.  On my last flight  , mixture all the way in (rich) , same power setting 17gph, same alt, tit stays on my hottest stays at 1540, did notice that when i started at idle cold & i pushed forward on throdle it hesitated a bit until it warmed up 

[Chessieretriever]

I had a similar problem in my rocket many summers ago. It would go away when I added the electric boost pump and turned out to be a failing engine driven fuel pump.On my bird I have to add the boost pump when climbing above 12,000 or the fuel flow is insufficient for the big TSIOL-550 even when everything is perfect. Perhaps you have fuel pressure before and after to confirm?

Either way you were flying leaner on the flight you are describing (higher temps and lower fuel flow).

[carusoam]

You fine gents,

May want to add your plane details next to your avatars...

It will help the memory impaired amongst us.  (Or just me)

Best regards,

-a-

[jlunseth]

Hi Aaron.  "tit hottest cyl" doesn't make sense.  There is only one TIT and it is not measured at any cylinder, it is Turbine Inlet Termp., its measured at the turbo.  I believe you are thinking of Engine Gas Temp, EGT can be measured at each cylinder, so you can have a "hottest" and "coolest" EGT.  The engine driven fuel pump is a very good possibility for your problem.

[N201MKTurbo]

13 hours ago, Aaron Lachman said:

thank you guys in advance , i’m flying a m20k 252 tse with the rocket conversion , my usual power setting is 31 MP , 2300rpm , burning 18gph , mixture knob back one inch 10k ft .tit hottest cyl 1540 f.  On my last flight  , mixture all the way in (rich) , same power setting 17gph, same alt, tit stays on my hottest stays at 1540, did notice that when i started at idle cold & i pushed forward on throdle it hesitated a bit until it warmed up 

We are having the same problem with a rocket. The mechanic just sent the fuel pump out for repair. I'll let you know how it goes. It should be back soon.

Edited November 22, 2017 by N201MKTurbo

[Aaron Lachman]

thank you for input 

[jlunseth]

The other possibility to check out is your fuel control.  It is not common, but the controls have been known to fail or jam.