Hot starting issues

[Davidv]

I’m hoping someone can help out with a question for a new bravo owner.  I’ve had some issues with hot starts here I try the boost pump for as little as 2 seconds, as much as 10, waiting the required amount of time to crank again, ect...

The engine generally starts pretty well when it’s cold but this seems to happen right after right after a fuel stop.  Has anyone else had a similar issue?

[AustinAir]

I have had success by applying full throttle, mixture rich, boost pump on 6-8 seconds, then throttle idle, mixture cut, starter engage and advance mixture 3/4 as engine fires and advance throttle as needed. When I have encountered issues that this process did not resolve I had a mag problem 

[mike_elliott]

Try shutting down at 1200 RPM and leaving the MP alone. After fueling, start cranking with mixture in idle cut off. After about 4 blades, slowly advance the mixture until about 1/2 way. If it hasnt caught by then, stop advancing the mixture. Crank for a few more seconds. If still no fire, Flood that sucker and do a flooded start. 

NOTE, Manifold pressure wont do anything while priming on a Lycoming, unlike on a continental. It could be in, out halfway etc, it doesnt make a difference on the Lycomings. Mixture is what regulates what goes into the cylinders with the boost pump on.

[Bob_Belville]

10 minutes ago, mike_elliott said:

Try shutting down at 1200 RPM and leaving the MP alone. After fueling, start cranking with mixture in idle cut off. After about 4 blades, slowly advance the mixture until about 1/2 way. If it hasnt caught by then, stop advancing the mixture. Crank for a few more seconds. If still no fire, Flood that sucker and do a flooded start. 

NOTE, Manifold pressure wont do anything while priming on a Lycoming, unlike on a continental. It could be in, out halfway etc, it doesnt make a difference on the Lycomings. Mixture is what regulates what goes into the cylinders with the boost pump on.

Is MP something like a throttle?  I know mine is a lowly IO360 but I only have 3 engine/prop whatyoumaycallits.

[Davidv]

Thanks everyone.  We couldn’t get it started so stuck here in Atmore, AL for now.  We think it could be a mag problem even though they have less than 100 hrs.  Thank you Slick mags!  Getting it uncowled here shortly and we will see...

[LANCECASPER]

I put mixture in full when I hit the boost pump and wait about 15 seconds for the fuel to vaporize.  Then I back off on the mixture half way before I start cranking it. 

With the Bravo you need everything in the ignition system to be top notch or you'll have problems starting it (good mags that are timed well, good ignition harness, good plugs (preferably fine wire), and a good starter. Mine starts well, but hot starts in the summer in Texas can be a problem. After hearing good things, I bought a Slick Start but I haven't had a chance to get it installed yet.

[midlifeflyer]

There was a thread here about the time I joined. It described a procedure for a hot start in a J which can't possibly work. Makes no sense  at all.  

No boost pump. Mixture rich, throttle full 10-20 sec, throttle ¼-½ ".  Mixture off & advance to start. 

So I fly out to lunch on a warm day. Try "the book" method when I leave. No go. Figured what have I got to lose and tried it. Started immediately and every warm/hot start since.

No idea whether it would work on any other model. 

 

[jaylw314]

1 minute ago, midlifeflyer said:

There was a thread here about the time I joined. It described a procedure for a hot start in a J which can't possibly work. Makes no sense  at all.  

No boost pump. Mixture rich, throttle full 10-20 sec, throttle ¼-½ ".  Mixture off & advance to start. 

So I fly out to lunch on a warm day. Try "the book" method when I leave. No go. Figured what have I got to lose and tried it. Started immediately and every warm/hot start since.

No idea whether it would work on any other model. 

 

I'm guessing it allows any built up pressure in the fuel lines to leak out a little extra fuel into the intake.  Either that, or it's a psychological ploy to keep people from screwing things up

[ArtVandelay]

There was a thread here about the time I joined. It described a procedure for a hot start in a J which can't possibly work. Makes no sense  at all.   No boost pump. Mixture rich, throttle full 10-20 sec, throttle ¼-½ ".  Mixture off & advance to start. 

 

 

The reason it works is because it dumps all the hot fuel and vapor out of the fuel lines (you will see your fuel pressure drop). When you start cranking the cool fuel cools the fuel lines and doesn’t vaporize quickly so you get fuel through your injectors, not vapor.

 As explained to me by an AP/M20J owner.

 

Tom

 

[midlifeflyer]

@jaylw314 & @ArtVandelay, So there actually is an explanation!

Anyway, it works (even if just to avoid screwing things up :)).

Edited January 30, 2019 by midlifeflyer

[Bob_Belville]

43 minutes ago, midlifeflyer said:

No boost pump. Mixture rich, throttle full 10-20 sec, throttle ¼-½ ".  Mixture off & advance to start. 

 

Can you amplify?

• I suppose I can add the word "crank" between the word "full" and the "10-20".
• Then you stop cranking, pull the mixture to off and the throttle to the 1/4"-1/2" position and
• then start cranking again? 

[GLJA]

Had same issue in my F (IO-360A1A). Only "foolproof" way I've found to start (warm or hot... or any time after the engine has been running and require a restart) is:
Mixture Rich
Throttle Full
Booster Pump on 3-5 seconds
Mixture Full lean
Crank and slowly pull throttle towards idle. 

Once it catches, advance mixture to rich to keep engine running. 

[jaylw314]

14 minutes ago, Bob_Belville said:

Can you amplify?

• I suppose I can add the word "crank" between the word "full" and the "10-20".
• Then you stop cranking, pull the mixture to off and the throttle to the 1/4"-1/2" position and
• then start cranking again? 

No, he was meaning (sorry if I'm putting words in your mouth @midlifeflyer)

• Mixture full rich
• Throttle full
• Wait 10-20 seconds with your hands in your lap
• Mixture idle
• Throttle 1/4"-1/2"
• Then crank, advance mixture when it catches

The point is that you just push those two knobs forwards and literally do nothing for a few seconds

[mike_elliott]

7 minutes ago, GLJA said:

Had same issue in my F (IO-360A1A). Only "foolproof" way I've found to start (warm or hot... or any time after the engine has been running and require a restart) is:
Mixture Rich
Throttle Full
Booster Pump on 3-5 seconds
Mixture Full lean
Crank and slowly pull throttle towards idle. 

Once it catches, advance mixture to rich to keep engine running. 

Thats the flooded engine start

[GLJA]

2 minutes ago, mike_elliott said:

Thats the flooded engine start

Yep. And I'll quote my AME: "It's better to deal with the Devil you know, than the devil you don't"

[mike_elliott]

Yes it is..If you dont know what state the air/fuel mixture is in, put it in a state you do...Flood it, then start it.

 

[Davidv]

Update on my issue: we removed the left mag and found tiny droplets of water inside.  When we got that out and cleaned the rest we got a spark and were able to takeoff.  However, it looks like I’ll have to overhaul the mags less than 100 hrs after they were installed, too many wearing parts inside...

[Niko182]

ouch. might consider taking a look at electroair. people gain fuel economy and speed, and hot starts aren't a problem anymore. everyone that owns one claims it starts on the second blade. no matter if its hot, cold, freezing, flooded or what ever. 2 blades and it starts.

[mike_elliott]

One of the 2 major weak points of the TIO540 is the Slick mags. The other is the constant vigilance of the exhaust system condition. BUT it could be starter adaptors, new cylinders before TBO, cracked spinner back plates, etc....

[Awful_Charlie]

As my previous engine got past TBO, I was getting hot start problems, as well as occasional problem on the ground when it was *very* hot (ie 40dC plus) and with less than third or so tanks. Turned out the engine fuel pump needed an overhaul: with the new engine (including pump) it starts after a couple of blades when using the POH method

[midlifeflyer]

15 hours ago, jaylw314 said:

No, he was meaning (sorry if I'm putting words in your mouth @midlifeflyer)

• Mixture full rich
• Throttle full
• Wait 10-20 seconds with your hands in your lap
• Mixture idle
• Throttle 1/4"-1/2"
• Then crank, advance mixture when it catches

The point is that you just push those two knobs forwards and literally do nothing for a few seconds

They are the correct words

It is  pulled from my checklist where "start" means "turn the key." I could have been clearer.

Edited January 31, 2019 by midlifeflyer

[LANCECASPER]

15 hours ago, Niko182 said:

ouch. might consider taking a look at electroair. people gain fuel economy and speed, and hot starts aren't a problem anymore. everyone that owns one claims it starts on the second blade. no matter if its hot, cold, freezing, flooded or what ever. 2 blades and it starts.

Not available for a M20M.

[Davidv]

This is probably a dumb question, but I assume Bendix mags won’t fit in that tight space?  Also, can anyone recommend the set of mag/spark plug/other ignition components that will at least reduce the risk that I get stranded at a random airport?

[mike_elliott]

20 minutes ago, Davidv said:

This is probably a dumb question, but I assume Bendix mags won’t fit in that tight space?  Also, can anyone recommend the set of mag/spark plug/other ignition components that will at least reduce the risk that I get stranded at a random airport?

Continental/Bendix mags are not approved for the Lycoming TIO540. A shame.

[Davidv]

2 minutes ago, mike_elliott said:

Continental/Bendix mags are not approved for the Lycoming TIO540. A shame.

Thanks Mike - yes, I know the POH calls for the slicks but wasn’t sure if you could do it anyway.  I had heard of some people who demanded that Lycoming put them on a new factory reman and eventually Lycoming agreed.  However, fitting them in that tight of a space in the M20M installation is another story...