Revisiting Hot Start Recommendations

[Jeff_S]

Hello all. I found and resurfaced this thread yesterday about hot starts:

http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=2&threadid=211

But since it's in the Vintage forum perhaps many folks aren't going there, so in my interest of learning whether others have newer or different ideas about how to perform this procedure I thought I'd cross-post it here.

If there's nothing more to say, so be it...just wanted to give folks the opportunity.  Thanks!

[Ned Gravel]

For me, a hot start is any start within 40 minutes of the previous shutdown (in the summer) and 20 minutes in the winter.  Shut down is always done at 1200 RPM with mixture pulled to idle cutof.

Hot start is  basically "touch nothing and crank."

 

HOT ENGINE START

Cowl Flaps                       OPEN

Master                              ON

Throttle                            Set at 1100-1200 RPM (as per shutdown)

Propeller                           Full Fine

Mixture                             Idle Cut Off

Check                                “Clear Prop”

Mixture                             Right Hand Ready

Magnetos                        Crank 15-20 turns

Engine Catches               Full Rich

Throttle                            1100 RPM

Oil Pressure & Temp      “GREEN”

Mixture                              Full Lean for taxi

 

It normally takes 5 to 8 blades.

[Magnum]

IMHO the best cure for hot start problems is a Skytec Starter. After installation I checked for the correct 28V wiring because it turned the prop so fast. My procedure: Mixture full rich, fuel pump for 1 sec (to decrease vapor in the fuel lines), mixture cut off, throttle open 1 inch. Engine starts within 1-2 sec.

[Lood]

I've had my share of hot start struggles, but fortunately have it under control at this stage. I have a question though, as I have been caught out once or twice.

If your first hotstart attempt is unsuccessfull, or rather if you were too slow to catch it, what do you do next? Repeat the procedure or proceed to a flooded start? I've been too slow with the mixture on a couple of hot start occasions which resulted in the engine tturning over a few times and then dying. In these situations, I really battled to get the engine going.

[Ned Gravel]

Since I put the Skytec starter / Concorde sealed battery combination in, I have had no problems with hot starts.  Before that happened, I would do a flooded start if the hot start procedure did not work.  Takes more time and cranks the engine more till it catches though.

 

[ltdoyle]

I have hot/flooded start procedures on my checklist....

[Buster1]

Itdoyle, can I ask a potentially dumb question?  All your speeds on your checklist are in MPH...do some Mooneys have MPH for A/S indicators?  Everything I fly is in KIAS (Cessna, Piper) or KCAS (F-16).

[ltdoyle]

Older Mooneys (mine is a 1965 M20E) have their airspeed indicators in MPH....

[flight2000]

Mine has both.  MPH is the outer ring and KTS is the inner ring.  The owners manual and checklist I use list everything in MPH. 

Brian

[flight2000]

Sorry, duplicate post...

[ltdoyle]

I stand corrected.  The airspeed is mph on the outer ring and knots on the inside.  The POH and performance figures are in MPH.....

[Immelman]

One trick I've adopted to the above "dont touch anything -- throtle cracked mixture cut off, crank" hot start procedure is to turn on the electric fuel pump. This is because I would often find that while the engine reliably caught with the above procedure, it would run for a few seconds and then quit. With the boost pump ON and mixture cut off in the IO-360, no fuel is being introduced prior to advancing the mixture -- I do this just to keep positive fuel pressure going into the servo as the engine starts.

Anyway, this trick works pretty well for me an ensuring reliably easy hot starts.

[67M20F]

I do a cold start anything after about 1hr and have no problems starting, but I only prime for just a few sec, unless its cold out and it sat for awile, then I will give it a good prime of about 6-7 sec, and it fires right up.

[Skybrd]

Quote: Lood

I've had my share of hot start struggles, but fortunately have it under control at this stage. I have a question though, as I have been caught out once or twice.

If your first hotstart attempt is unsuccessfull, or rather if you were too slow to catch it, what do you do next? Repeat the procedure or proceed to a flooded start? I've been too slow with the mixture on a couple of hot start occasions which resulted in the engine tturning over a few times and then dying. In these situations, I really battled to get the engine going.

[jetdriven]

I have noticed that we sometims need boost pump to keep the engine running after a hot start.  Fuel in the lines vapor locks after 10-15 minutes.  I learned my hot start technique, the "dont touch anything 1000 RPM method" from David at All-American.  It works.

[carusoam]

 

Jet driven,

 

Did David tell you to keep turning the key after it first starts?

 

Same procedure for IO550, but if you don't keep the starter engaged for a few seconds, it dies and becomes a roulette game to start after that.

 

Best regards,

-a-

 

[FlyDave]

My hot start procedure (from my mechanic) works every time in my 201:

1. 
   
2. Mixture - Full rich
   
3. Prop - High RPM
   
4. Throttle - Full open
   
5. Master on
   
6. Boost pump for ~1 second
   
7. Throttle - crack to idle (works anywhere from 700 - 1200+ RPM)
   
8. Start engine - it will take anywhere from 5-10 blades
   

This procedure has not failed me once in 250 hours of flying.

I believe it's different in a continental.

[Lood]

Well, in the meanwhile, I've installed a Skytek starter. All I can say is: It don't take any bulls..t from any start - be it cold, hot or in between.

[jetdriven]

Carusoam, David didnt cover that because it always started right up.  I will ask him about that though. I have noticed you sometimes need the boost pump on for a stable fuel flow right after start.

[Shadrach]

1. Mixture idle cutoff

2. Master on.

3. Throttle is set for about 1000-1100 or 1/4" (I consider 1000rpm a minimum idle speed for the Lyc 360s)

4. Cowl flaps open

5. Engage starter.

6. Engine will typically cough a few times, stay on the starter and be ready on the mixture for when the "coughs" become "power pulses" (hard to describe, but you'll know it when you see and feel it) and smoothly go full rich.

7. Once engine is running, lean mixture way back until you get a raise in RPM.

I do not see how running the boost pump at idle cut-off makes a difference, but I'd like to learn why those that do feel that it does?  At idle cut-off (boost pump or not) there is no pressure at the flow divider and there is no method for purging what's in the system...  I think it's cross over from guys who've flown Continentals, which do have a fuel/vapor return to the tank.

 

[jetdriven]

In our IO-360 sometimes you give it the mixture, it runs a few seconds, then dies.  It wont keep fuel pressure.  Running the fuel pump for that kind of hot start allows full fuel pressure to hit the flow divider and injectors as soon as the mixture is pushed in.  The 201 engine gets pretty heat soaked after 10-20 minutes.

[Shadrach]

Interesting... I'd never occured to me that would make a difference.  I don't even bother to prime my F in the fall and winter if the engines cold. I just crack the throttle, mixure rich and crank...fires off in 2 or 3 blades.

[jetdriven]

Ours started in 10-15 blades at 25 degrees with no prime.  Maybe we should just skip priming altogether.

[Skybrd]

I think I will try Jetdriven suggestion of first turning on the boost pump when the mixture is fully back and do the normal hot start method. I think it will work but will probably try it first in front of my hanger, in case it doesn't work.  I also have a Skytec starter and sure it helps with the increased friction of a hot engine.  I also have a question: If you shut down the engine with full lean mixture settings, how can it be restarted with the mixture in the shut off position. Where does the fuel come from ??

[John Pleisse]

Skybrd-I think I will try Jetdriven suggestion of first turning on the boost pump when the mixture is fully back and do the normal hot start method. I think it will work but will probably try it first in front of my hanger, in case it doesn't work.  I also have a Skytec starter and sure it helps with the increased friction of a hot engine.  I also have a question: If you shut down the engine with full lean mixture settings, how can it be restarted with the mixture in the shut off position. Where does the fuel come from ??

It's in the bowel. If you push the mixture in prior to starting, you are releasing the hounds. Just crank until it catches and push your mixture. Typically, you still have a second or two. Also, I put that Skytec in...it really made a difference. I stopped ruining batteries instantly.