Too much fuel flow???

[MichaelFarley56]

I was thinking about this thread today as i got my Waiex up for a quick flight and wanted to snap a few quick photos of my mixture (I hope I'm not beating a dead horse here!):

As we talked about, when I first get ready to start the engine I prime using the mixture, and then set it around here for engine start, taxi, and runup:



As I taxi onto the runway, I apply rull rich mixture and then advance the throttle, normally giving me a rolling max RPM of around 3050-3100. Today, as i was climbing, I recorded max EGT readings of around 1180 and my hottest cylinder hit around 320.

Once power is pulled back to cruise (3050-3150, just like Charlie), i readjust the mixture for around a 1250 degree EGT reading (+/- 50 degrees or so), which keeps my cylinders nice and cool. Today the hottest settled in right around 305. Mixture position in cruise is around here:


Here's a shot of my panel, running just a little rich but close to where I like it right after level off:



Ultimately, I may lean my needle valve a quarter turn or so once it's warm here, but for regular maintenance, I normally do a 1/4 turn lean adjustment in the spring, and a 1/4 turn rich adjustment in the fall. Otherwise, the needle is pretty much left alone. Not perfect but it works!

[Sonex1462]

Thanks for the pictures and info. I am still some time away from my first flight. But I am beginning to thinks about things like this.

John Stewart
Sonex 1462

[Fastcapy]

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[MichaelFarley56]

You know Mike, I've never actually taken a ruler to measure the total mixture control travel (I will next time I'm at my hangar), but I'd guess that my first picture (ground runs), the mixture is around 2/3 pulled of the total travel, and my cruise setting (second pic) i have the mixture pulled around 1/3 of the total travel.
I know I'm off on the numbers but a starting point would be that there's a total mixture travel of around 3". For me it's full rich for takeoff, pulled 1" in cruise, and 2" at idle on the ground. Or something similar...

Does that help at all?

[Fastcapy]

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[rizzz]

With all this chasing the mixture in various flight phases, what do people do when doing aerobatics where you're adjusting the throttle all the time? Just set it full rich and run really rich at the times you pull the throttle back (like coming out of a loop)?

[fastj22]

With all this chasing the mixture in various flight phases, what do people do when doing aerobatics where you're adjusting the throttle all the time? Just set it full rich and run really rich at the times you pull the throttle back (like coming out of a loop)?

Yes.

[rizzz]

With all this chasing the mixture in various flight phases, what do people do when doing aerobatics where you're adjusting the throttle all the time? Just set it full rich and run really rich at the times you pull the throttle back (like coming out of a loop)?

Yes.

Alright, thanks, I'll have to see if this carb works for me.
I'll give it a good try anyway.

[radfordc]

With all this chasing the mixture in various flight phases, what do people do when doing aerobatics where you're adjusting the throttle all the time? Just set it full rich and run really rich at the times you pull the throttle back (like coming out of a loop)?

I do put the mixture to full rich for full throttle operation, but I haven't noticed any problems doing aerobatics. When you pull the throttle to idle on the back side of a loop the engine isn't really going to slow down to idle speed.

The only time I need to pull the mixture really lean is when idling on the ground in order to get a smoother and slower idle speed.