Hot Starting

[Badmoonraising]

My cold starting has improved dramatically since changing to a method recommended by my AME. But hot starting is another matter. It truly is a PIA (pain in the ass). Those with fuel injection; can you share a method that works?

[N6018Q]

Basically leave your controls in the same position you shut down with. Throttle around 1000 rpm, mixture out, and turn the key. When it starts, add mixture. There are several posts on here that describe it better than I can but this works for me.

[NJMac]

That's exactly what works on my E too. Found a check list here that listed that and showed it to my instructor. He said it would never work. Sure as snot, it does.

Basically leave your controls in the same position you shut down with. Throttle around 1000 rpm, mixture out, and turn the key. When it starts, add mixture. There are several posts on here that describe it better than I can but this works for me.

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[J0nathan225]

I also have had much better luck with the above method after nearly draining my battery and grinding my starter from failed hot start attempts previously. Now I shutdown with 1000 RPMs then mixture out. If refueling or quick turn I will open the oil filler hatch to help more hot air escape. Climb in dont touch throttle or boost pump, just turn the key and slowly give it mixture, takes about 5-15 secs of cranking and slowly advancing mixture, but it works! 

[charlesual]

It helps me make sense of it by realizing that the fuel injection spider sits on top of a hot engine. When you shut down, fuel boils down into the cylinders. Essentially you’re cylinders are already primed when doing a hot start. If you add throttle or mixture (even a small amount) you’ll flood your engine.


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[ArtVandelay]

It helps me make sense of it by realizing that the fuel injection spider sits on top of a hot engine. When you shut down, fuel boils down into the cylinders. Essentially you’re cylinders are already primed when doing a hot start. If you add throttle or mixture (even a small amount) you’ll flood your engine.

If it was fully primed, it would kick off immediately.? My AP told me on longer stops to push both throttle and mixture forward for about 10 seconds or more to clear the fuel lines, then return to normal positions and do the start, the fuel lines will then be filled with cooled fuel.

[Bartman]

If I shut down and restart within just a few minutes such as a quick turn fuel stop the method described above works for me. If it is a longer stop like lunch then it does not work as well. In this case I typically leave the mixture at idle cutoff and advance to full throttle for flood start and it actually starts quicker than the first method, at least for my plane. 

[Yetti]

IF you stop for lunch then probably just do a cold start. Or only run the fuel pump for like 3 seconds.

Hot start.

Shut down with throttle at 1100 RPM.

Dont touch anything.

Turn key and crank.

When it pops, slowly add mixture.

 

Edited July 21, 2018 by Yetti

[jaylw314]

3 hours ago, teejayevans said:

If it was fully primed, it would kick off immediately.? My AP told me on longer stops to push both throttle and mixture forward for about 10 seconds or more to clear the fuel lines, then return to normal positions and do the start, the fuel lines will then be filled with cooled fuel.

That actually primes the system a little more, which isn't necessarily unhelpful.  When you push the knobs forwards, any built up pressure in the lines is allowed to push any remaining fuel out the injectors, but now the lines in the hot areas are filled with vapor, not cooled fuel (at least on our Lycomings).  It just adds a tad more prime before starting.

If "fully primed," yes, it should start immediately, but the idea is most hot starts are "more than fully primed," so you have to wait to suck enough air into the intake.

Seems the options are:

1. Crank with the perfect amount of fuel in the intake (as described above)
2. Crank with less or no fuel in the intake, and add fuel while cranking (give it a blip of mixture while cranking)
3. Crank with too much fuel in the intake, and crank for a longer time (prime with full mixture for 3 seconds or more)
4. Crank with way too much fuel in the intake, and use the hot start procedure (flood the engine and use a flooded start)

Practically, I'll use the procedure above (shut down at 1100 RPM and don't touch the throttle), and it'll work about 75% of the time with about 4-5 seconds of cranking.  The other times, it'll die before I can give it enough mixture or if my reflexes are bad.  If it does, I've found I can just go full rich and run the pump for 1-2 seconds, and then cranking again without touching the throttle yet.  I'll end up having to crank for a couple seconds longer, but that's not long enough to be worth fooling around with the throttle.

On the very rare occasion that is not successful (it's only happened once or twice),  I'll resort to a "partial flooded" start.  I'll give it about 1/2 throttle, full rich, pump on for 3 seconds, then mixture idle and pump off.  Then I'll start it like a flooded start, but because the throttle only partly forward, the two-handed dancing with the flooded start is a little easier and less chance of racing the engine.

TL,DR; lots of options and they all should work

[St64]

Don Maxwell has a good post on youtube where he demonstrates starting and stopping a hot engine.

[Badmoonraising]

Thanks for the info. At least the message is consistent. I will look for the video 

[HRM]

I thanked all the posts that describe what I do, works every time and I live in Tejas.

Maxwell Link

[Steve65E-NC]

I struggled with this problem for several decades.  Put in the better Sky-Tec starter and purchased a Concorde GX-35 battery.  Problem went away. 

[DonMuncy]

Maybe it only works in Texas  

[bob865]

I'm part owners on my plane and my partner and I are oposites.  He has no problem cold starting, but can't hot start to save his life.  I have some trouble sometimes cold starting, but have never had trouble hot starting.  Funny how that works. 

Anyway, to hot start, I don't touch anything.  I leave it exactly how it was when I shutdown.  It will not start for me in this configuration, but after the engine turns over a couple of times (2-3 blades) at idle cutoff, I start adding mix until she fires but never going above half mix.  Once she starts to run, I'll go full rich to purge the lines and once running smoothly, lean for taxi.  It also seems to start better if I have the boost pump on when I do this to make sure I have a stable fuel pressure.  If I don't, the fuel pressure will drop out of the green arc when she starts to fire and takes a bit to recover.

So far, has worked everytime I stop for fuel and try to restart. 

[jaylw314]

1 hour ago, bob865 said:

I'm part owners on my plane and my partner and I are oposites.  He has no problem cold starting, but can't hot start to save his life.  I have some trouble sometimes cold starting, but have never had trouble hot starting.  Funny how that works. 

So if both of you fly everywhere, you're golden