Starting a hot IO-540

jmpoplin

jmpoplin

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Jun 7, 2010
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Alamogordo, NM
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NCFlyer
In the past few weeks I've made stops for fuel, dropping pax off, etc and trying to get my hot IO-540 started is like me trying to fly by flapping my arms.

Looking for tips and tricks for a hot start and/or flooded start too!

Thanks,
Jeff
 
Mixture full rich, throttle full forward. Run boost pump until fuel pressure indication, or roughly three seconds. Idle cut off, throttle closed, crank, and then advance mixture after it fires. Works every time with my AEIO 540, and starts after a few blades, although not as well as a cold start.
 
My method is similar, and works on every injected 540 I've flown for a hot start from Aztec to Navajo:

1) Throttle forward, mixture idle cut-off
2) Fuel pump on
3) Mixture forward for 1-2 seconds (leave fuel pump on)
4) Engage starter
5) When engine catches (not the first "I think I can" when it actually starts firing), mixture forward, throttle back to idle
6) Fuel pump off

If you take my engine course, you'll find out why that works...

A similar variant works for injected Continentals as well, although their injection systems work significantly differently.
 
It's a matter of eliminating the vaporized fuel in the fuel line on a hot day. I've had success using the hot start technique one of my CFIs who flies Chieftains demonstrated. Mixture forward, throttle 1/4" open, no prime/no boost pump, usually starts within 5-6 blades. If it doesn't I use Ted's method. Cold start is the same as hot except I prime for 3-5 seconds with the boost pump. Also, my POH says run boost pump whenever the ambient is above 80F and it seems to like it, particularly above 90F when on the ground. Mixture at idle cutoff/open throttle is the trick for a "flooded" start, advancing mixture as engine fires. Throttle position to control rpm.

btw, are you based at UBS?
 
Ted DuPuis said:
A similar variant works for injected Continentals as well, although their injection systems work significantly differently.
Click to expand...
It seems that I used the method you described on the various Continental TSIO-520s I operated in various C-206s a 210 and the 320.
 
I use something similar to Ted's description:
1. Prime with the fuel pump (clear out vaporized fuel)
2. Mixture cut-off, throttle full forward.
3. Crank, while slowly retarding the throttle.
4. When it catches, slowly bring the mixture in and the throttle back.


It's so easy to write, that it ignores the fact that you need three hands to do it.
 
Steve said:
It's a matter of eliminating the vaporized fuel in the fuel line on a hot day. I've had success using the hot start technique one of my CFIs who flies Chieftains demonstrated. Mixture forward, throttle 1/4" open, no prime/no boost pump, usually starts within 5-6 blades. If it doesn't I use Ted's method.
Click to expand...

That's why I started using my method. The aforementioned method works for me about 75% of the time. My method works for me 99% of the time. Being able to hot start an Aztec both engines the first time is great party trick, not to mention easier on the starters.

Everskyward said:
It seems that I used the method you described on the various Continental TSIO-520s I operated in various C-206s a 210 and the 320.
Click to expand...

On the 310 I fly, the primer is a toggle switch separate from the fuel pump switches. So my standard method is a bit different (and works 95% of the time), however sometimes on hot starts the standard method floods the engine, at which point I use the method I mentioned.

TMetzinger said:
It's so easy to write, that it ignores the fact that you need three hands to do it.
Click to expand...

That's the other thing I like about my method - it works just fine with two hands, and if you get the timing right, the engine goes right into a nice idle. It really irks me to see most pilots start (especially hot start) where the engines rev up to 1500+ RPM. Not good for them, and looks unprofessional. Your passengers will appreciate it if your engines starting more closely resemble their car than their weed whacker.
 
Ted DuPuis said:
TOn the 310 I fly, the primer is a toggle switch separate from the fuel pump switches. So my standard method is a bit different (and works 95% of the time), however sometimes on hot starts the standard method floods the engine, at which point I use the method I mentioned.
Click to expand...
I don't remember the 320 having a separate primer switch but that was a long time ago.
 
I just crack the throttle with the mixture closed and then advance the mixture once she fires...Ive never seen this fail to work on a Chieftan/Jo...its out company policy
 
I was told if it will hot start without the prime you reduce the flooding potential and excess fuel on the ground issue. I'd say it works often enough for me to continue to prefer it. Sometimes you just have to do what you have to do, though.
 
taters said:
I just crack the throttle with the mixture closed and then advance the mixture once she fires...Ive never seen this fail to work on a Chieftan/Jo...its out company policy
Click to expand...

My instructor told me to do that on his Navajo. I tried it on the right engine, it failed. He tried it on the left engine, it failed. Then he said "Screw it, just start it like your Aztec." Although I do hear it works most of the time. And if it's your company policy, then that's what you do to keep the boss happy.

Steve said:
I was told if it will hot start without the prime you reduce the flooding potential and excess fuel on the ground issue. I'd say it works often enough for me to continue to prefer it. Sometimes you just have to do what you have to do, though.
Click to expand...

That's if you do the excess flooding method, where you try to pump all the vaporized fuel out of the lines prior to starting. That involves having the mixture open 5+ seconds with the fuel pump going. This just gets some fuel in.
 
jmpoplin said:
In the past few weeks I've made stops for fuel, dropping pax off, etc and trying to get my hot IO-540 started is like me trying to fly by flapping my arms.

Looking for tips and tricks for a hot start and/or flooded start too!

Thanks,
Jeff
Click to expand...

You may also have a mag going/gone bad. I fought with a TIO-540 for a few months thinking it was just a hot start problem and found the problem went away when I replaced the mag.
 
PittsDriver said:
You may also have a mag going/gone bad. I fought with a TIO-540 for a few months thinking it was just a hot start problem and found the problem went away when I replaced the mag.
Click to expand...

A good point... but 99% of pilots I see are just doing it wrong, and blame the engine.
 
Capt. Geoffrey Thorpe said:
You don't have these problems starting cars with the control systems that I help design.:raspberry:
Click to expand...

Correct, but those systems also have various undesirable failure modes.

I prefer mechanical fuel injection for piston aircraft.
 
I usually just depended on magic.

or flood it until fuel is running out onto the ground. then mixture idle and crank :)
 
I keep pushing levers back and forth 'til it starts.

Works every time. :D
 
This is the procedure I use for starting the AEIO-540 on the Pitts S2B:

1) Throttle and mixture full forward (notice sudden increase from zero on the full pressure indicator, then decrease back to zero);
2) Fuel pump on for one second, then off (notice sudden increase from zero on the full pressure indicator, then decrease back to zero);
3) Mixture full lean, throttle 1/3 - 1/2 in;
4) Engage starter;
5) When the engine gives a few solid fires, mixture full forward, throttle "cracked open".

But whatever works - it seems every Pitts pilot has their own way to start the AEIO-540!
 
Last edited:
You guys are making me enjoy my carb'd O-470 even more than I already did! ;)
 
denverpilot said:
You guys are making me enjoy my carb'd O-470 even more than I already did! ;)
Click to expand...

The carbureted engines have starting advantages, but the fuel injected engines have lots of other advantages, and as such give me a fuel injected engine any day. Remember, these engines are built to run, not to start. Your car is built more to start than anything else.
 
Well, for one, I definitely can't run LOP successfully with our engine, but that also means that I get to ignore the flamefests online on the topic, too. ;)
 
Ted DuPuis said:
My method is similar, and works on every injected 540 I've flown for a hot start from Aztec to Navajo:

1) Throttle forward, mixture idle cut-off
2) Fuel pump on
3) Mixture forward for 1-2 seconds (leave fuel pump on)
4) Engage starter
5) When engine catches (not the first "I think I can" when it actually starts firing), mixture forward, throttle back to idle
6) Fuel pump off

If you take my engine course, you'll find out why that works...

A similar variant works for injected Continentals as well, although their injection systems work significantly differently.
Click to expand...

I tried this today on my Commander 114B and this method does work.

Clarification question - #3 - I am assuming that you bring the mixture back to idle cut off after priming for 1-2 seconds? Engage starter #4. At that point, I did slowly enrichen mixture. It took two tries at this to get the engine to fire up.
 
Stephen Shore said:
I tried this today on my Commander 114B and this method does work.

Clarification question - #3 - I am assuming that you bring the mixture back to idle cut off after priming for 1-2 seconds? Engage starter #4. At that point, I did slowly enrichen mixture. It took two tries at this to get the engine to fire up.
Click to expand...

Yeah I think he omitted that part of the step in his write up. You have to go back to cutoff before engaging the starter. If you tried to crank with the electric pump running and the mixture full rich the engine would immediately flood during the cranking, or even without cranking.

The fact remains that Lyco injected setups are a PITA to hot start because there's no way to legitimately purge the lines of vapor without flooding the engine to varying degrees. This is because the heat soaked mechanical fuel pump and downstream lines lack return lines, unlike the Continental setups. The general Lyco hot start procedures delineated on most POHs basically rely on the electric fuel pump being able to purge the lines during the starting attempt itself, which is almost always unsuccessful. Thence, most people fall within some personal OWT preference of varying durations of engine flooding, since that's all you can do with a Lyco. Except of course to wait for the lines to liquify/cool on their own and drain, at which point normal cold start priming procedures are applicable again. That of course is a non-starter of an option for those of us trying to get somewhere on the same day (see what I did there? ;)).

Starters are cheaper than TCM cylinders, so that's my rationalization for putting up with the hassle of hot starting a Lyco. Once they're running, they also tend to not grenade inflight to a much higher degree than TCM engines; another rationalization for my choice :D
 
I had no issue starting Lycoming engines in the Aerostar.
1. Mixture and throttle full forward.
2. Boost pump on high for three seconds.
3. Boost off
4. Mixture to cut off
5. Boost to low
6. Start the engine, catches on second cycle of the prop almost every time. As it catches push mixture to rich and pull throttle back to idle.

For Continental I use prime instead of high boost and then depends on engine setup if boost is needed.

Sent from my SM-J737T using Tapatalk
 
I'm still learning my IO400 but the difference between hot and cold starts has come into focus. Cold- prime and start with mixture full rich. Hot- prime and start with mixture at idle cutoff. Either way it fires right up. Sometimes "the book" is the problem. But I have electronic ignition so priming a hot motor may work differently with mags.
 
It took me until I saw Denver post to realize this was 7 year old thread lol

My go-to for hot starts has always been just throttle full open and mixture cut off, then slowly advance mixture and retard throttle. Pump / prime / boost depends on plane. In the Cirrus you really don't need more than quarter open in throttle, just mixture cut off and advance slowly
 
Ted DuPuis said:
My method is similar, and works on every injected 540 I've flown for a hot start from Aztec to Navajo:

1) Throttle forward, mixture idle cut-off
2) Fuel pump on
3) Mixture forward for 1-2 seconds (leave fuel pump on)
4) Engage starter
5) When engine catches (not the first "I think I can" when it actually starts firing), mixture forward, throttle back to idle
6) Fuel pump off
.
Click to expand...


Same here for my TIO540 except usually fuel pump needs to remain on. That hot engine needs a lot of cool air to start.
 
Tantalum said:
.....My go-to for hot starts has always been just throttle full open and mixture cut off, then slowly advance mixture and retard throttle. Pump / prime / boost depends on plane.....
Click to expand...

This works for me, no boost pump.
 
Stephen Shore said:
I tried this today on my Commander 114B and this method does work.

Clarification question - #3 - I am assuming that you bring the mixture back to idle cut off after priming for 1-2 seconds? Engage starter #4. At that point, I did slowly enrichen mixture. It took two tries at this to get the engine to fire up.
Click to expand...

You are correct that at #3 after the few seconds it goes back to idle cut-off. I didn't enrichen mixture while cranking at all, although I've seen some people do it. It's never worked for me.

As to starter reliability, in the 1,000 hours I had my Aztec, I think I put one starter on each engine. Granted I typically flew long legs.

Meanwhile, I was watching some CAP pilots who had no clue how to hot start the 182... be completely unable to start it the other day. I thought about going over but I just shook my head.
 
Ted DuPuis said:
Meanwhile, I was watching some CAP pilots who had no clue how to hot start the 182
Click to expand...
They probably had about three dozen forms to fill out as a result of that event..
 
Ted DuPuis said:
My method is similar, and works on every injected 540 I've flown for a hot start from Aztec to Navajo:

1) Throttle forward, mixture idle cut-off
2) Fuel pump on
3) Mixture forward for 1-2 seconds (leave fuel pump on)
4) Engage starter
5) When engine catches (not the first "I think I can" when it actually starts firing), mixture forward, throttle back to idle
6) Fuel pump off

If you take my engine course, you'll find out why that works...

A similar variant works for injected Continentals as well, although their injection systems work significantly differently.
Click to expand...

I was taught this way and it has always worked for me. :cool:
 
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