Any tips for high DA engine starts?

K

Kynadog

Pre-Flight
Joined
Jan 19, 2019
Messages
56
Display Name
Display name:
Kynadog
I see all kinds of advice on how to lean for takeoff at high density altitude (in this case 7,000+ feet). My question is do you adjust the mixture when starting the engine? It seems that if you left the mixture full rich, it would be too rich to support combustion.

Any tips for High DA engine starts?
 
I never had to adjust the starting procedure at high DAs (and I learned in the summer when the field elevations were 6000+, let alone DA). Full rich supports combustion just fine. You just don't get maximum power until you peak it out which we did at run up.
 
I have an IO-390, starts are always with the mixture at idle cutoff. If cold I 1st run the fuel pump with cutoff rich, for a bit. When ‘lukewarm’ I may do a touch of fuel pump, virtually none if hot.

The throttle is at a normal idle position. Once it lights off, plenty of time to take the mixture out of cutoff, to a ‘ground leaned’ position.

This was the procedure from the engine installer, been working. With all the different setups, can easily be something else recommended with your particular engine. A few times when I’ve tried something else, it hasn’t worked as well.
 
Kynadog said:
IO-550. Cold.
Click to expand...
I tried starting my IO-550 once at a high DA airport (8,000' or so) with the mixture somewhat leaned, with no success.
What works for me is start with the mixture knob full rich, then lean for ground ops once the engine is running.

- Martin
 
i am routinely starting a NA IO-470 at DAs at or above 8,000’ and the answer is “no”.
 
Mags, Master, Clear Prop, Starter... Lean before take off for max power.
 
Having lived in Denver and flown mountain airports for 20 years, other than not going to full rich in those fuel-injected airplanes in which you increase mixture as you turn the key (and backing it out immediately after start in those in which you don't) I've never seen a difference from a sea level start.
 
Martin Pauly said:
I tried starting my IO-550 once at a high DA airport (8,000' or so) with the mixture somewhat leaned, with no success.
What works for me is start with the mixture knob full rich, then lean for ground ops once the engine is running.

- Martin
Click to expand...


Works everytime...
 
You must log in or register to reply here.
Back
Top