Engine Starting

[PT20J]

1 hour ago, bradp said:

@PT20J Skip are you an aeronautical engineer in real life?  You have a ton of Mooney specific engineering knowledge.  

I'm a retired electrical engineer. The only aviation project I worked on during my career was a flight simulator back in the early '90's. I owned a 1978 J at the time and we used it as a test bed. I got to know the VP of Engineering and a couple of engineers at Mooney at the time and we shared some data. I also had several consultants working on the project. I learned a lot on that project and it and started a fascination with aerodynamics and flight dynamics.

[Robert C.]

5 hours ago, buddy said:

Robert have you tried this, cold start everything full forward high boost pump 3-4 seconds throttle back to 1/4 in. Open and should start on one blade. Hot start, everything full forward low boost pump10 seconds, pull throttle back and as you start cranking push the throttle in slowly and by the time you get to 3/4 throttle it should start without a problem. This always works for me.

Buddy

Thanks Buddy, I'll try that hot start procedure. Sounds like a variation on the flooding method mentioned above for the Lycoming.

[N9201A]

Robert have you tried this, cold start everything full forward high boost pump 3-4 seconds throttle back to 1/4 in. Open and should start on one blade. Hot start, everything full forward low boost pump10 seconds, pull throttle back and as you start cranking push the throttle in slowly and by the time you get to 3/4 throttle it should start without a problem. This always works for me.
Buddy

I’ve had my J 20+ years but it’s never started on ONE blade. I hope to see this someday and learn how to do it.

[N9201A]

Thanks Buddy, I'll try that hot start procedure. Sounds like a variation on the flooding method mentioned above for the Lycoming.

What is condition of mag/ignition components? After various techniques/plugs/timing remedies/OWTs, bullet bitten = mag OH remedied my issues.

[carusoam]

9 hours ago, N9201A said:

 

I’ve had my J 20+ years but it’s never started on ONE blade. I hope to see this someday and learn how to do it.

 

Interesting thought.... what causes that?

As the first blade passes by...

• Compression is working
• air is flowing
• ignition is working
• timing is working

The only thing not working yet... Fuel flow.

If the engine was shutdown using mixture at ICO...there isn’t much vaporized fuel where it needs to be on that first blade or two going by...

 

Shutting the engine down using the ignition key may lead to a different challenge... excess fuel left behind....

A consistent start is greatly appreciated....

Starting on the first blade or second? Not as important... 

 

PP thoughts only, not a CFI...

Best regards,

-a-

[lifendet]

Update.... Aircraft fixed. Culprit left mag.. 

Edited February 12, 2019 by lifendet

[larrynimmo]

attached is my current checklist card for a 1981 M20J with a Lycomming engine

mooney_m20j_N1144W.doc

on the back page, it gives you instructions for "Hot Start" & "Flooded engine start"

I hope that it helps....it always works for me

 

Edited February 12, 2019 by larrynimmo
added info

[Guest]

On 2/10/2019 at 12:56 PM, jaylw314 said:

The IO-360 A3B6 starts on the left magneto only.  I believe the A3B6D also starts on the left magneto only even though it is a dual-drive magneto (I'm only guessing on that).

Early J models had ignition switches which grounded the right magneto during start.  Service instruction M20-59 corrected the error.  Those who have switched to the IO-360A3B6 may have to revisit this, depending on whether dual impulse magnetos are used.

Clarence

[jaylw314]

5 minutes ago, M20Doc said:

Early J models had ignition switches which grounded the right magneto during start.  Service instruction M20-59 corrected the error.  Those who have switched to the IO-360A3B6 may have to revisit this, depending on whether dual impulse magnetos are used.

Clarence

Whoa!  I hadn't seen that before!  How does this work?  Wouldn't the right mag fire too early during starting and cause kickback?

[Guest]

3 minutes ago, jaylw314 said:

Whoa!  I hadn't seen that before!  How does this work?  Wouldn't the right mag fire too early during starting and cause kickback?

Removing the jumper from the ignition switch on early J models improved the starting by allowing the right magneto to fire while cranking.  The D3000 series magneto uses one impulse coupling to fire both mags.

If the jumper is not installed the right magneto fires in the normal position 20-25 BTDC and can kick back at low cranking speeds. 

Clarence

[jaylw314]

2 hours ago, M20Doc said:

Removing the jumper from the ignition switch on early J models improved the starting by allowing the right magneto to fire while cranking.  The D3000 series magneto uses one impulse coupling to fire both mags.

If the jumper is not installed the right magneto fires in the normal position 20-25 BTDC and can kick back at low cranking speeds. 

Clarence

Ah.  So with the A3B6, there is no danger of kickback because the right mag is turning too slow to make any spark at all, not because it's grounded.  I assume that means it only helps with starting inasmuch as once the motor starts turning, it starts firing right away rather than having to wait for the ignition switch to be turned back to BOTH, right?

If that's the case, I'm guessing mine still has the R mag grounded during start, since I recall when my left magneto was bad, the motor would not fully catch if I just kept cranking.  however, if I turned it back to BOTH, sometimes the engine would start.

Edit: oh, never mind, I was confused.  It took me a moment to realize you said A3B6 owners would need to reinstall the jumper to ground the right mag during starting.

 

[PT20J]

The ignition switch only grounds out the right mag (when the jumper is installed) in the Start position.

Bendix_Ignition_Switch_Maintenance.pdf

sim20-59a.pdf

[Shadrach]

On 2/10/2019 at 1:49 PM, PT20J said:

Actually, it depends on whether you have the jumper on the ignition switch or not. No jumper = both mags for start. 

Does each mag have an impulse coupling?

Edit - Thanks Clarence.

Edited February 13, 2019 by Shadrach

[Davidv]

19 hours ago, lifendet said:

Update.... Aircraft fixed. Culprit left mag.. 

I had the same issue on my IO-540 a few weeks ago, bad impulse coupler in the left mag.  Turned out there was also water that had made its way inside but we replaced the mags anyway.  Just like you I originally thought it was a hot start issue but after trying many things over several hours (stranded in a tiny unattended airport at night away from home), we eventually came to the conclusion it was the mag.

[lifendet]

On 2/13/2019 at 10:21 AM, Davidv said:

I had the same issue on my IO-540 a few weeks ago, bad impulse coupler in the left mag.  Turned out there was also water that had made its way inside but we replaced the mags anyway.  Just like you I originally thought it was a hot start issue but after trying many things over several hours (stranded in a tiny unattended airport at night away from home), we eventually came to the conclusion it was the mag.

Glad it worked out. Same situation, end up driving 7 hrs to get home in a rental. Friend flew me back 2 days later to pick her up. She was happy, I was happy and 2.5 hrs later we were home. My pocket wasn't so happy but I can live with that. 

[bradp]

If you have a high speed light weight starter you can generate sufficient RPM to retract the pawls on the left and if you let go of the ignition and the right is no longer grounded, the right may catch at higher RPM as well.  

For individual mag owners I’ve heard of some of the experimental crowd swear by dual impulse coupled mags.   Anyone have dual impulses?  Downsides beside one more mechanical thing that can fail? 

BTW my  thread from about 6 months ago was the left mag resulting in inability to start hot no matter the technique but pretty okay cold starts.  Slick mag.  Points worn.  250 hrs since overhaul.  Hiiiighly recommend Aaron Williams. He did a good job.  Honest broker.  I was happy  to fork over the reasonable repair cost to him.  

[jaylw314]

12 minutes ago, bradp said:

If you have a high speed light weight starter you can generate sufficient RPM to retract the pawls on the left and if you let go of the ignition and the right is no longer grounded, the right may catch at higher RPM as well.  

Yeah, I was guessing that was why I could sometimes start the plane with a weak left mag.  I could crank forever with no luck, but I cranked for a few seconds and let go, sometimes the engine would catch.

[ArtVandelay]

Slicks eat points for breakfast, I would consider replacement on a 400 hour timetable.


Tom

[Marcopolo]

19 hours ago, bradp said:

For individual mag owners I’ve heard of some of the experimental crowd swear by dual impulse coupled mags.   Anyone have dual impulses?  Downsides beside one more mechanical thing that can fail? 

TSIO-360 GB dual impulse couplers!