Trouble setting idle below 1000 rpm

[Matthew P]

Have an IO 360 a1a that we can't get to idle below 1000 rpm, it spits and spudders...tried adjusting mixture, cleaned injectors, but can't get it below 1000 without it running extremely rough...any suggestions?

[KSMooniac]

You likely have an induction leak somewhere... Troubleshoot that first.

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[tony]

you might want to pull the finger screen while you're looking for leaks

[Shadrach]

Textbook induction leak symptoms. Likely have a cylinder/cylinders pulling unmetered air through one or more of the intake gaskets into the manifold under the high vacuum of closed throttle operations. Small variances in mixture make a large difference under such conditions. An intake leak will make the proximal cylinder run lean.

 

[Ragsf15e]

Maybe make sure the sniffle valve is closing as well.  It’s the drain on the bottom of the engine.  Simple ball in a seat.  Maybe not enough to cause all your symptoms, but???

[Jim Peace]

I am sure this is unrelated but my O-360 did not idle well for a long time until last month.  Below about 800 rpm it always felt like it would quit until very warm....I had both of my mags overhauled and my annual done with C&W in Caldwell NJ and my plane has never idled so well now.  Maybe it was a mag issue or maybe they did some mixture adjustment....or both..

[Matthew P]

4 hours ago, Jim Peace said:

I am sure this is unrelated but my O-360 did not idle well for a long time until last month.  Below about 800 rpm it always felt like it would quit until very warm....I had both of my mags overhauled and my annual done with C&W in Caldwell NJ and my plane has never idled so well now.  Maybe it was a mag issue I had or maybe they did some mixture adjustment....or both..

Thanks, so far we found an induction leak and that the adjustment blocks were way out, it has gotten significantly better, looking at mags next, going to a surefly on left side...

[Ragsf15e]

23 hours ago, Matthew P said:

Thanks, so far we found an induction leak and that the adjustment blocks were way out, it has gotten significantly better, looking at mags next, going to a surefly on left side...

I have a left side SF and it’s great. Consider putting it on the right side and rewiring the key so that neither mag is grounded during start.  I believe @jetdriven has done this.  It now starts on all plugs.

[AJ88V]

Not sure

3 hours ago, Ragsf15e said:

I have a left side SF and it’s great. Consider putting it on the right side and rewiring the key so that neither mag is grounded during start.  I believe @jetdriven has done this.  It now starts on all plugs.

Not sure if this has been addressed elsewhere on the forum, but posting here.  I just came out of annual and Surefly was very high on my list of 'upgrades'.  However, my A&P, who has been a big proponent, says he's seeing problem with accelerated plug wear (massive electrodes) on the order of 50 hour replacement and destruction of plug harnesses.  In fact, he suffered a rough engine from this on a recent 'rescue' flight he was making in his airplane, ultimately determined to be a fried harness. Evidently, Surefly is coming out with new plug harnesses, but that won't address the accelerated plug wear.  YMMV

[Matthew P]

1 minute ago, AJ88V said:

Not sure

Not sure if this has been addressed elsewhere on the forum, but posting here.  I just came out of annual and Surefly was very high on my list of 'upgrades'.  However, my A&P, who has been a big proponent, says he's seeing problem with accelerated plug wear (massive electrodes) on the order of 50 hour replacement and destruction of plug harnesses.  In fact, he suffered a rough engine from this on a recent 'rescue' flight he was making in his airplane, ultimately determined to be a fried harness. Evidently, Surefly is coming out with new plug harnesses, but that won't address the accelerated plug wear.  YMMV

Surefly recommends new harness to be installed at the time of installation, from what I understand the trouble is when individuals either go with the thin wire or cheap harnesses

[Ragsf15e]

1 hour ago, AJ88V said:

Not sure

Not sure if this has been addressed elsewhere on the forum, but posting here.  I just came out of annual and Surefly was very high on my list of 'upgrades'.  However, my A&P, who has been a big proponent, says he's seeing problem with accelerated plug wear (massive electrodes) on the order of 50 hour replacement and destruction of plug harnesses.  In fact, he suffered a rough engine from this on a recent 'rescue' flight he was making in his airplane, ultimately determined to be a fried harness. Evidently, Surefly is coming out with new plug harnesses, but that won't address the accelerated plug wear.  YMMV

Ive got close to 400hrs on mine with fine wire plugs.  Installed a new harness when it was first put on. Haven’t had any issues at all with the plugs or the harness.

[A64Pilot]

On 9/12/2024 at 5:15 PM, AJ88V said:

Not sure

Not sure if this has been addressed elsewhere on the forum, but posting here.  I just came out of annual and Surefly was very high on my list of 'upgrades'.  However, my A&P, who has been a big proponent, says he's seeing problem with accelerated plug wear (massive electrodes) on the order of 50 hour replacement and destruction of plug harnesses.  In fact, he suffered a rough engine from this on a recent 'rescue' flight he was making in his airplane, ultimately determined to be a fried harness. Evidently, Surefly is coming out with new plug harnesses, but that won't address the accelerated plug wear.  YMMV

IF there is a higher amperage which results in a hotter spark and I think that the point, then you will get accelerated plug wear.

Automobiles dealt with this years ago with exotic plugs, Iridium etc. so maybe fine wires would live normal lives with a Surefly?

[Shadrach]

@Matthew P

I suggest you solve your idle issue before swapping in a Surefly. Generally speaking, it’s not a great idea to add new variables when troubleshooting. If you can isolate the issue to the mags then so be it, but I would work on getting the power plant running properly before I started modifying it.

[Matthew P]

15 minutes ago, Shadrach said:

@Matthew P

I suggest you solve your idle issue before swapping in a Surefly. Generally speaking, it’s not a great idea to add new variables when troubleshooting if you can isolate the issue to the mags then so be it, but I would work on getting the power plant running properly before I started modifying it.

I am, I'm not expecting that the SF would "fix" anything.

[Shadrach]

17 hours ago, Matthew P said:

I am, I'm not expecting that the SF would "fix" anything.

It's not just about what you expect or don't expect, it's about solving the idle issue before adding a new variable.  As good as Surefly products have been, they have not been trouble free.  There have been software issues that specifically relate to start up and low RPM operations. If your idle situation is not completely resolved before adding a new component that has an issue and it manifests as a symptom that is similar to your previously unresolved issue, systematic trouble shooting becomes convoluted at best. 

[Matthew P]

2 hours ago, Shadrach said:

It's not just about what you expect or don't expect, it's about solving the idle issue before adding a new variable.  As good as Surefly products have been, they have not been trouble free.  There have been software issues that specifically relate to start up and low RPM operations. If your idle situation is not completely resolved before adding a new component that has an issue and it manifests as a symptom that is similar to your previously unresolved issue, systematic trouble shooting becomes convoluted at best. 

I thought I made that understood that I understand that, evidently not...so...I understand that...thanks

[MikeOH]

2 minutes ago, Matthew P said:

I thought I made that understood that I understand that, evidently not...so...I understand that...thanks

I understood that,...I think