Hot Start procedure on IO550

[mooneyflyer]

Can folks share their effective hot start procedure for IO550?
Thanks

[Brandt]

2 minutes ago, mooneyflyer said:

Can folks share their effective hot start procedure for IO550?
Thanks

Well, I suspect you’re going to get a lot of responses, but in short I think the most important thing is to run low boost long enough to get cold fuel into the lines - as much as 60 seconds. Then a very brief prime and a short prayer. 
 

But a quick followup question about brand of oil and spark plugs to use could make this vie for longest response thread on the forum…

[Rick Junkin]

The info in this article may help - it amplifies @Brandt's recommendation. There are recommended procedures for both Continentals and Lycomings - I've used the recommendations on my TIO-540 and they work well. https://www.aviationconsumer.com/maintenance/hot-starting-science-and-art/

Cheers,
Rick

[anthonydesmet]

One thing I would add after shutdown is open your oil door. Letting some of the heat out of engine compartment to prevent vapor lock in your fuel lines will help with the start after your stop over. I added this to my TSIO - 360 procedures and have never had an issue after a short stop.

[Healthpilot]

18 minutes ago, anthonydesmet said:

One thing I would add after shutdown is open your oil door. Letting some of the heat out of engine compartment to prevent vapor lock in your fuel lines will help with the start after your stop over. 

I do the same thing. I also found this video useful for IO550: 

 

[atpdave]

This is what works for me (IO-550G(7)B):

1. Throttle to idle, mixture to idle cutoff

2. High boost pump on for 15-20 seconds to purge fuel vapor upstream of engine driven fuel pump

3. Throttle to normal cold start position, mixture still in idle cutoff

4. Crank while slowly advancing mixture to rich

5. When engine catches - mixture rich, low boost pump on immediately until stable idle, then off (5-10 seconds).

This technique is a combination of Lycoming and Continental recommended hot start procedures and it works every time for me.  Let me know how it works for you.

 

[carusoam]

Chances of needing to use a hot start procedure are really slim….

The engine often tells you if you listen closely….

If you hear the fuel boiling in the injection system…. Follow the hot start procedure…

 

The IO550 in the LB is unique in the way it is plumbed….

Pull the mixture knob back… throttle in…. Run the boost pump….  This circulates cool fuel through the system and then back to the tank….

thus cooling the fuel system, and stopping the boiling…

 

Then it becomes an ordinary start sorta….

 

First determine if you need a hot start…

Typical things that make the fuel system boil…. High power on hot days…

Usual Long XCs, with ordinary descents and landings… Things cool so well, the hot start isn’t needed.

If the plane has been sitting for 15 minutes… things have cooled A lot….

 

most of this detail is in the POH… but, it doesn’t come with the details of what is going on and why… 

PP thoughts only,

-a-

[GeeBee]

I have seen all kinds of techniques and a lot depends on how good your ignition system is maintained. I keep mine really tight. I've done the POH method, I have done others, here is the one I like the most for the IO-550

1. Do not change throttle position from shut down.

2. Place mixture full rich

3. Crank engine, when it catches, be ready with a short burst of low boost if it starts to die. About 80% of the time a short toggle (not too much or it will die) of the boost pump is required, 20% it just comes up to idle.

I like this procedure for the following reasons:

1. It has never failed

2. You do not have an RPM burst on start that you have to "two hand"

3. There is not a lot of fuel both in the engine or on the ground from the sniffle port. (Less chance of fire)

4. Any fuel you boost into the engine is immediately consumed within the engine.

5. If it does fail (and it never has for me) you can go with the POH procedure with little chance of too much fuel around the engine.

[Mufflerbearing]

What @GeeBee said is what I do and as he stated, it has not failed for me either.  However, as he also stated, a great ignition system is important.  After installing fine wire plugs my hot start issues became a thing of the past and my lop is excellent.

[FJC]

On 2/2/2022 at 5:32 AM, GeeBee said:

I have seen all kinds of techniques and a lot depends on how good your ignition system is maintained. I keep mine really tight. I've done the POH method, I have done others, here is the one I like the most for the IO-550

1. Do not change throttle position from shut down.

2. Place mixture full rich

3. Crank engine, when it catches, be ready with a short burst of low boost if it starts to die. About 80% of the time a short toggle (not too much or it will die) of the boost pump is required, 20% it just comes up to idle.

I like this procedure for the following reasons:

1. It has never failed

2. You do not have an RPM burst on start that you have to "two hand"

3. There is not a lot of fuel both in the engine or on the ground from the sniffle port. (Less chance of fire)

4. Any fuel you boost into the engine is immediately consumed within the engine.

5. If it does fail (and it never has for me) you can go with the POH procedure with little chance of too much fuel around the engine.

Method above is what I use and works well (IO-550 on '97 Ovation).

[Steve Yucht]

I have tried many techniques and settled on the following:

1. Mixture rich
2. Throttle in about 7 turns (for me its my index fingertip on the tapered side of the nut)
3. Low boost pump on 6 seconds and then off
4. Crank and slowly turn throttle in if she doesn't catch within 4-5 seconds

This works well even just stopping for fuel in the FL summer for 15-20 min.

[Alan Maurer]

This is my way....Mixture full lean...all the way out....throttle all the way in....full throttle......low boost for five seconds, then off...

crank engine...it will start.....mixture in ...throttle back quickly....all set

[flyingcheesehead]

Here's a foolproof way that does NOT require three arms or hands.

First, purge the lines as atpdave and carusoam describe above, with full throttle, mixture cutoff, and pump on. I like to do this by switching to the right tank and leaving the door open, because you can hear the sputtering of the return line in the right tank. When it stops sputtering, the purge is complete.

Second, prime the engine exactly as if it's a cold start - Throttle a few turns in from idle, pump on and mixture rich for a few seconds, you know the drill because you do it all the time.

Third: Pump off, all three engine controls firewalled. Start cranking (left hand) while simultaneously pulling the throttle slowly back with your right hand. It'll catch and start, and since you're already pulling the throttle toward idle it's very easy to avoid the "zoom" that most techniques cause.

[Niko182]

If its hot, everything full forward. Mags on. Hit the starter, and recline the throttle as the starter is running. Around the 50% mark, it usually catches.

[TGreen]

1. Mixture rich 

2. Throttle in about one inch 

3. Low boost 15 seconds, then off

4. Crank ignition and pray

5. Throttle back quickly to 1000 rpm after it catches 

[Cruiser]

if you know you will be hot starting the IO-550, set the power to high idle, and pull the mixture to stop the engine. 
When you are ready to start back up, do not touch the power, RPM is high and MIXTURE full rich. 
Do not adjust anything else or try to purge, cooling, prime or whatever else you want to call it. Just engage the starter, it will fire and run on its own
Be ready to use LOW BOOST if the engine stumbles. It should need BOOST for only a couple seconds. 

This procedure is from the Continental factory reps at one of the Mooney conventions several years ago. 

[Niko182]

14 minutes ago, Cruiser said:

if you know you will be hot starting the IO-550, set the power to high idle, and pull the mixture to stop the engine. 
When you are ready to start back up, do not touch the power, RPM is high and MIXTURE full rich. 
Do not adjust anything else or try to purge, cooling, prime or whatever else you want to call it. Just engage the starter, it will fire and run on its own
Be ready to use LOW BOOST if the engine stumbles. It should need BOOST for only a couple seconds. 

This procedure is from the Continental factory reps at one of the Mooney conventions several years ago. 

This is the method I was taught. I just recline as its starting so i dont look like a cirrus pilot firewalling it on start.

[Cruiser]

9 minutes ago, Niko182 said:

This is the method I was taught. I just recline as its starting so i dont look like a cirrus pilot firewalling it on start.

Any power more than idle is dangerous. There have been several "close encounters" because of high power starts.

 

[M20F]

There are a million ways to start it hot with 2 blades which practice gives.  The question is to what to do when it doesn’t start and you do things to make it continually worse. 
 
When all else doesn’t work boost it to flood it, full throttle/no mixture, crank, when it fires adjust the 2 knobs. 
 
This question gets asked all the time and the answer people are looking for is how to make it work when it doesn’t. 

[Pinecone]

6 hours ago, M20F said:

When all else doesn’t work boost it to flood it, full throttle/no mixture, crank, when it fires adjust the 2 knobs.  

When I was doing a good bit of flying in a friend's T-34A with IO-550, I did all (hot or cold) starts this way.  No issues.

Edited May 19, 2022 by Pinecone

[thinwing]

On 2/15/2022 at 10:52 PM, Alan Maurer said:

This is my way....Mixture full lean...all the way out....throttle all the way in....full throttle......low boost for five seconds, then off...

crank engine...it will start.....mixture in ...throttle back quickly....all set

this was my go to method 

[KLRDMD]

On 5/19/2022 at 4:00 AM, Pinecone said:

When I was doing a good bit of flying in a friend's T-34A with IO-550, I did all (hot or cold) starts this way.  No issues.

Until you have an engine fire after intentionally flooding it, as happened to a friend of mine.