Hard starts after leaving the plane outside

[Flying074]

My wife and I have a 1967 M20F ( IO-360 A1A). It is in good condition, with only about 160 hours on the engine since overhaul. Whenever she flies to an overnight destination, the next day the plane is extremely difficult to start. Out of the hanger, it starts easily. We have troubleshot many of the common issues -  boost pump, P-leads, fuel flow, battery charge, and there doesn't seem to be a problem. Does anyone have any idea what might cause this? Humidity? We keep the plane hangared in North Carolina  with a dehumidifier running. Leaving it out overnight on the East Coast subjected to more humidity than normal. Could that be a contributing factor? She has used cold start, hot start, and flooded engine procedures.  I know this is minimal information, but I am a deployed servicemember and unable to get my hands on the airplane myself for a more thorough analysis.  She is an Air Force pilot with several thousand hours of turbine time, but less experienced troubleshooting 50-year-old reciprocating engines.   Appreciate any help or advice. We're both big fans of the forum.  

[RLCarter]

Sounds like an ignition issue, Shower of Sparks and/or a Magneto?

Edited June 12, 2017 by RLCarter

[carusoam]

1) +1 for starting ignition challenges...  what does the plane have ignition wise to aid the starting process.  Shower of sparks or any modification to the ignition system?

2) Got any JPI data you can pull from? Spark plug resistance may show up here...  there is a place to send the data to, Savvy...

3) starting procedure, lets review what is being done to get ready.  How much fuel, throttle position, anything else?

4) outdoors, and humidity are not usual challenges for starting an IO360, unless there is moisture in the fuel...

PP thoughts that come to mind...

Best regards,

-a-

 

 

Edited June 12, 2017 by carusoam

[StevenL757]

Agree with RLC.  From a blind perspective, it sounds like the battery is working fine, but you may have a spark plug issue.  Do you know how old the plugs are, and what type they are (massive or fine wire)?  Sounds like they need a good cleaning or replacement.  Very happy you're on the forum...a lot of collective wisdom and experience here.

Regards, Steve

[RLCarter]

Forgot to mention, Welcome aboard and Thank both of you for your Service

[N201MKTurbo]

My overnight procedure is to just set the throttle to the 1000 RPM position, mixture rich and just crank till it starts. Don't run the boost pump at all. It will often start then run for a few seconds and then quit. The next attempt it will start and run fine.

The engine will still be flooded but cold. A little different then a hot start.

[Marauder]

I couldn't gather from your post what process you are using to start. I've owned my F model for 26 years and have been based on the east coast the entire time.

For starting after sitting like you describe, I would have the throttle set for roughly 1,000 RPM, mixture full rich and run the boost pump until I get full pressure. I then pull the mixture to full idle cut-off and start cranking. Once it catches, mixture full in and then once running, leaned.

The only variation is if it really cold. I will let the boost pump run for an additional few seconds.


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[Yetti]

Cold start:

1" of throttle

Boost pump on

Mixture to open

count to 6 (if cold maybe a bit longer)

Close mixture

Crank

Mixture to a bit above half when fires

Reach quickly to bring throttle down. to 1100-1200 rpms

 

How many hours on the mags?

Edited June 12, 2017 by Yetti

[Flying074]

Thanks to everyone for your thoughts on this so quickly.  We are going to have the spark plugs and injectors cleaned which should be a good first step.  If there is still a problem we'll come back up and seek some additional guidance (and share what the A&P thinks).  Our cold start procedure is what Yetti lays out above.  It usually works well but has been a challenge recently.  We have shower of sparks ignition and the mags have about 400/450 hours respectively (I don't have my logs to confirm but both getting close to 500).  

The collective wisdom is a lifesaver unless we're trying to get to bed and start going down a rabbit hole of Mooney talk.  Appreciate everyone's help!

[M20F]

I don't see how any of the things listed explain in hanger it starts perfectly, out of hanger it starts bad.  If it is a mechanical issue it is going to have difficulty starting in/out of hanger.  

Does she sump the tanks?

[Dream to fly]

To the O.P.  you stated that stored in a humidity controlled hanger you have no issues but if left outside there are issues.  I have questions.

- if inside when started does the engine pop off and run smooth?

- How long outside before you have issues. several hours? overnight?  what if you wait till mid day (morning dew evaporates)

- How does it start once you do get it started, any hints, black smoke, coughs, surges

[Oldguy]

On a car, I would look for cracked ignition wires that lose enough spark the cylinders won't fire or a cracked distributor cap. For the plane, it might do well to have the mechanic check the resistance of the plugs before he cleans them. @carusoam mentioned resistance earlier as many planes have seen their plugs from one company look fine but have so much resistance they are essentially dead and cleaning will do nothing to improve them.

But the start-fine-inside-overnight versus not-start-fine-outside-overnight is puzzling. Please update us on the solution you discover.

[Bob - S50]

Is the hangar heated?

[takair]

I'm with RL that it may be shower of sparks.  The contacts are possibly corroded and arched.  Perhaps humidity makes it worse.  The shower of sparks is one of the most ignored part of our aircraft and makes a night and day difference in starting.  I suffered through hard starts for a long time until I cleaned the contacts in the unit.  Rather easy job if you still have the hatch in front of the windshield.  One way to tell if it is shower of sparks related is that the engine tends to buck and bang a little just as it starts up.

[Yetti]

Google.   Egap hard starts

[RLCarter]

8 minutes ago, Yetti said:

Google.   Egap hard starts

Add in a little moisture, a few carbon tracks and now you have a starting issue. A buddy puts a light bulb next to the mags on his Ag-Cat to keep the moisture at bay, Hot days, cool nights and a Sea Breeze off the Gulf of Mexico doesn't help

Edited June 13, 2017 by RLCarter

[bradp]

Turn off the humidifier in the hangar and see if it reproduces the problem? 

[Flying074]

 Thanks again to everyone who has posted something in this. We cleaned the plugs (they were not fouled, but better safe than sorry)  and soaked the injectors in solvent.   The mechanic did tighten some leads that vibrated loose. The most interesting was the ignition housing inside the cockpit. When we turn the key to start it actually torqued the ignition housing which may have compromised or grounded the wiring. It's possible that caused enough juice to flow to crank the starter, but we weren't getting full spark from the magnetos. Upon inspection, the magnetos are still strong.   The plane started and flew home yesterday. We will try to replicate the problem over the course of the next few days and see if we can figure out why this only happens the day after a flight when left outside.  Whenever we have had problems, it's after overnight storage. 

 With the grounding issues resolved by cleaning and tightening the connections, I'm hoping we can solve this problem with technique, not technology. Will continue to keep everyone posted and thanks again to the Mooney community! We have certainly added to our list of starting procedures and will find the one that works best.  

 

[Yetti]

"Upon inspection, the magnetos are still strong."   What does that mean?   If the egap is worn, then you time the engine via procedure, then the timing actually shifts   and is not a true 25 degrees TDC. Was the timing checked?

 

"It's possible that caused enough juice to flow to crank the starter, but we weren't getting full spark from the magnetos. "    Why would this change from hangared to sitting outside overnight? 

[Guest]

If the internal timing of the magneto changes due to worn points or worn cams the magneto to engine timing does change.  Resetting the magneto to engine time to the specified value will have the spark occur at the correct time, the spark will not be as strong as it could be.

E gap is the efficiency gap, the internal timing of the magneto resulting in the strongest spark.

Clarence

[Yetti]

See it's good to have professionals around and set us armatures straight

[bradp]

What's an armchair armature? 

[N201MKTurbo]

2 hours ago, bradp said:

What's an armchair armature? 

Here is one:

 

Go ahead and figure this out....

[carusoam]

Armature, typically has wire windings that help generate power via a magnetic field in an electric motor...

Arm chair, typically used for resting a human body...

Amateur, the opposite of pro.... describes the artist who built the mannequin...

Mannequin, a mock up of a human being....

I see some wire, wrapping the chest in an armature-ish fashion, of the amateur built mannequin, that is clearly resting on an armchair...

Then I looked up the other armature...

https://en.m.wikipedia.org/wiki/Armature_(sculpture)

Way to go, Rich!  

Best regards,

-a-

[Grandmas Flying Couch]

I recently found corrosion in my shower of sparks from setting water, your is probably not that bad, but when I changed the Shower of sparks box the thing fires up fast!