Navajo Hot start procedures

[Treehawk]

Calling all experienced Navajo drivers!

A Chieftain with TIO 540 engines. It's 25 degrees C (and hotter), just shut the engines down. Within 10min you want to leave again. What is the best way to get these engines started?

Does anyone know a foolproof hot start method to get them going everytime?

thanks

[rigpiggy]

been a long time, but to best of my recollection boosts on, throttles/mixture full up for three seconds. boost off start in ico, as soons as it fires, mixtures lean.

[bater]

usually with ours....master on, mags on, starter on, advance the mixtures as it coughs, and they fire right up... takes about 3 seconds of cranking.

[Spinner]

usually have good luck that way as says Bater

I go mixtures rich, mags on and roll it over with throttles just above idle.

If she won't go then add some fuel via boost pumps 2-3 seconds.

If its barking and farting after start lean it a bit till the engine smooths out.

[wallypilot]

Never once failed me in Africa with 35-40 degree heat, and quick turn around

Throttles 1/2 open (i mean half way, not 1/2 inch)
Mixtures 1/2 open (again half way)

Obviously, mags on
Crank starter......if it doesn't catch right away, feather the boost pump a bit to get rid of the vapur lock, once it catches, enrichen (not necessarily full rich) mixture and throttle back close to idle. boost pump as necessary to maintain smooth running.

fuel vapour lock is your enemy here, as is the possibility of flooding the engine. Running the boos pump for a couple seconds helps evacuate the vapour. But, if you don't run it long enough, you don't get rid of all the vapour...too long and you flood the engine. hence, the procedure above. the throttle half open thing was simply from trial and error...can't tell you why it works. but it seemed to work better than throttle almost closed or full open.

[Hedley]

I really wish fuel injected Lycomings had return lines, like Continentals, which are a breeze to hot start.

My technique for hot fuel inj lyc:

Throttle and mixture full rich
boost pump 3 seconds
throttle back to 1/3rd open
mixture idle cutoff
crank

When it fires, mixture forward and boost pump on.

Note that my technique, like many others, intentionally floods the
engine. As you crank it with the mixture in cutoff (no more gas
into the engine) the fuel is purged and at some point there exists
a combustible mixture of fuel and air in the cylinders, and it
kicks.

Hot starts are a LOT harder with lightweight composite prop blades -
heavy metal blades have a lot more rotating inertia.

I really like the lightweight starters that crank ever so much faster
than the stupid heavy old prestolites.

[tripleseven]

If it wouldn't start with a normal hot start, I would just flood it, then use the flooded start. (Full throttle, idle-cut off until it fires, then set idle power.) Usually, I ended up doing some funky lever movements if it was puttering away, trying to settle into an idle. Worked every time.

[Dust Devil]

usually have good luck that way as says Bater

I go mixtures rich, mags on and roll it over with throttles just above idle.

If she won't go then add some fuel via boost pumps 2-3 seconds.

If its barking and farting after start lean it a bit till the engine smooths out.

[JZA]

Every Ho is slightly different.....

All I can say is Good Luck!

[grassroots]

As JZA said every Navajo is different. That being said I have flown three different vintages, all three had a slightly different hot start procedure in the POH, and all three procedures work.

[oncle]

throttles iddle
magneto on
fuel pump off
advance the mixture at full position and check your fuel pression
and wait 2 or 3 seconds you will se a little mouvement as soon close it. and start.with mixture off...
this one will start with a half tunr, and advance your mixture at 3/4. that it. and geven to me some news...

[Jim N]

I'm with tripleseven and DD on this one....Use the flooded start procedure.

Throttles open full.
Mixture ICO.
Boost pump CBs pulled.
Emerg. Boost pumps off.

Crank and it should start to catch after a few rotations. Leave the throttles open and advance the mixture lever to about ground lean. Pull back the throttle as the engine starts to rev up to speed. Only after it is running smoothly do you push the boost pump CB back in...

I've never been in places as hot as Wallypilot, but this technique has never failed me in 35-40 degrees Celcius, straight 'Ho (forget the boost CB) or Chieftain.

Good luck!

['effin hippie]

I always found 'em dead easy when they were really hot...

In a chieftan, if I recall, there's boost once the master is on.

So mix ICO

Throttles FULL

Mags ON

Starter and advance the mixture sloooowly

I remember what used to catch guys, including me, was when they were 'warm' and the above wouldn't do it. Then they were really easy to flood. And if you get too enthusiastic with the prime you are gonna wait a while.

Anyway, it's been a while since I was in a good 'Ho...

ef

edit: 'bater has it right too, I don't know how much the throttle position helps...

[Four1oh]

throttles at idle
start cranking,
slowly advance mixture till it catches.

was foolproof for me.

[Treehawk]

Big Thanks to everyone replying with suggestions. I really appreciate your time and your tips!

The starters will also thank you

TH

[shitdisturber]

OK if a Cessna 421 driver hijacks this thread? any tips on starting the GITSO engined on a 421 when it really hot? not doing too bad with the boost on low, mixture ICO, throttles about half, wait for it to fire, throttle back slowley, move miture up slowly, but the odd time the SOB just doesnt want to stay runing.{Oh, how I miss turbines!}

clunck, when it's misfiring try giving it a quick shot with the boost pumps; it works pretty well on a Ho, even in this miserable weather that southern Onterrible is blessed with these days.

[Benwa]

OK if a Cessna 421 driver hijacks this thread? any tips on starting the GITSO engined on a 421 when it really hot? not doing too bad with the boost on low, mixture ICO, throttles about half, wait for it to fire, throttle back slowley, move miture up slowly, but the odd time the SOB just doesnt want to stay runing.{Oh, how I miss turbines!}

Hey Clunk, on the 421 when it's really hot, I use about the same procedure as you, but when it doesn't want to stay running I turn the Fuel Pumps to OFF... usually the engines idle great afterward.

[185/310]

Well after some of those procedures, best would be if u just shutdown (10min) would be hit the master and hit the starter with the micture ICO, and throttles idle, engine catches then add mixture slowly otherwise engine will cough and possibly not start. If its really warm, pull the circuit breakers for the reg boost pumps, and do the same procedure, otherwise you'll flood the engine right away.

[Four1oh]

I recommend avoiding twin cessnas... at least the turbocharged ones... Piper's where it's at!

[Benwa]

The C421, flown & maintained by the right people, is a great aircraft ! Speed, comfort, silent cabin... and sexy looks !

[Hedley]

Just thought I'd remind everyone what gets forgotten so quickly ...

What cracks the heads on the 421 isn't pulling the throttle back quickly (that's more relevant for the turbo) ...

What cracks the heads on the 421 is jamming the mixtures forward during the descent. I land a 421 with props still at 1800 rpm, and the mixtures lean. In the rare event that I have to go around, then it's mixtures/props/throttles.

Contact Teledyne Continental for more information about this.

Back to your thread-jack about starting the 421 (never had any problem - I crank it with the boost pumps off, then after it fires, boost pumps low).

[Benwa]

Hedley,

same here, for the landing configuration. If we're solid IMC or aircraft on the runway..., we'll consider full rich, pitch fine @ the FAF...

[Raybanman]

I have to agree with most of the posts here, the big thing I've found is pull the CBs on the chieftain. I've flown the 310,325, and 350 and hardly ever had issues starting any of them hot with the CBs pulled when equipped.

CBs pulled
Throttle 1/2"
Mixture full rich
Boost on 3 seconds (gets rid of vapour)
Mixture ICO
Crank
Mixture full rich when it catches or after 3 blades whatever comes first
CBs in
Boost pump on for vapour lock

Works for me, but everyone has they're little dance they like to do

Cheers,
PP