Show Of Sparks Perpetually a problem

[druidjaidan]

When we first bought out bird (7ish years ago), the first thing that we discovered broken on my M20F right after we bought it was the SOS system. We didn't know how to recognize it (kicking back when starting), but it was failed when we picked it up. That turned out to be water ingress from a leaky windshield while the plane sat on a ramp in California while title issues were resolved.

A new SOS and resealed windshield later and we were on our way.  This lasted a couple years. We pick up the plane for annual and immediately notice the kick back and lack of buzzing. SOS issues again with a 2 yr old part.  Swap out the part for a used working one so we could get home. This worked for another year or so before more water found it's way into the SOS, no leaky windshield this time, but also no good answer for how water got in at all.  The mechanic (a different one local to my field) made a minor modification this time and drilled a few small holes in the bottom of the SOS case. I don't think it was replaced this time, but I don't recall.

Fast forward to the past year we pick up the plane from a long annual due to major engine maintenance and it won't start. No sound from the SOS. The whole picking up the plane to a failed SOS is getting really fucking old by this time. Mechanic pulls the SOS and bench tests it.  Failed. Takes it apart and cleans up the contacts, and other basic things, then throws a 12v power supply at it and it buzzes nicely. 

That gets me through to now.  It's been winter here and a long vacation away means I haven't flown in going on 2 months. I go out and the SOS has failed again.  We've replaced this thing almost as often as the oil and it just won't stay working.  We're stuck outside due to the combination of high cost (with the cost of hangars here we could replace the SOS every couple months and still break even) and a long wait list (4-5 years last I checked).

Anyone have any thoughts on how to improve the reliability here? This POS glorified solenoid has caused me way too many issues. 

Edited January 20, 2023 by druidjaidan

[Rjfanjet]

Slickstart Magneto Start Booster as a possible replacement. I haven't upgraded yet, just doing research. Available from Aircraft Spruce.

[Guest]

23 hours ago, druidjaidan said:

When we first bought out bird (7ish years ago), the first thing that we discovered broken on my M20F right after we bought it was the SOS system. We didn't know how to recognize it (kicking back when starting), but it was failed when we picked it up. That turned out to be water ingress from a leaky windshield while the plane sat on a ramp in California while title issues were resolved.

A new SOS and resealed windshield later and we were on our way.  This lasted a couple years. We pick up the plane for annual and immediately notice the kick back and lack of buzzing. SOS issues again with a 2 yr old part.  Swap out the part for a used working one so we could get home. This worked for another year or so before more water found it's way into the SOS, no leaky windshield this time, but also no good answer for how water got in at all.  The mechanic (a different one local to my field) made a minor modification this time and drilled a few small holes in the bottom of the SOS case. I don't think it was replaced this time, but I don't recall.

Fast forward to the past year we pick up the plane from a long annual due to major engine maintenance and it won't start. No sound from the SOS. The whole picking up the plane to a failed SOS is getting really fucking old by this time. Mechanic pulls the SOS and bench tests it.  Failed. Takes it apart and cleans up the contacts, and other basic things, then throws a 12v power supply at it and it buzzes nicely. 

That gets me through to now.  It's been winter here and a long vacation away means I haven't flown in going on 2 months. I go out and the SOS has failed again.  We've replaced this thing almost as often as the oil and it just won't stay working.  We're stuck outside due to the combination of high cost (with the cost of hangars here we could replace the SOS every couple months and still break even) and a long wait list (4-5 years last I checked).

Anyone have any thoughts on how to improve the reliability here? This POS glorified solenoid has caused me way too many issues. 

Aircraft Magneto Service of Montana, used to offer free testing and adjusting of SoS boxes.  It might be worth a call to them.  It sounds like yours is installed upside down if it fills with water.

[druidjaidan]

1 minute ago, M20Doc said:

Aircraft Magneto Service of Montana, used to over free testing and adjusting of SoS boxes.  It might be worth a call to them.  It sounds like yours is installed upside down if it fills with water.

Funny story, right after I posted this I stumbled across a maintenance for the TCM Starter Vibrator and it says basically the exact same thing: "Whenever possible, install the vibrator with the plastic cover up and data plate facing down.  If the starter vibrator is installed with the cover below the plate, drill a 1/8 in drain hole at the low point of the cover"

Mine is definitely installed with the plastic side down. I'll have to look and see if there is room to flip it since we have an interesting layout due to a 201 windshield. However, the drain hole has certainly been done. I'm going to go back out this afternoon and pull the thing myself.  I don't see how it could have water in it with the drains drilled out, but maybe it's getting corroded in the wet environment (Seattle).

[Andy95W]

The SlickStart is a great solid state option, but for the money you should just swap out the whole left magneto and SOS for a SureFly electronic mag.

[bcg]

A Bruce's cover would probably help it stay dry, mine comes pretty far up the cowling and covers the joints.

[0TreeLemur]

10 hours ago, Andy95W said:

The SlickStart is a great solid state option, but for the money you should just swap out the whole left magneto and SOS for a SureFly electronic mag.

Perhaps "could" is a better recommendation.  Some say that Surefly introduces a few potential issues.

[Ragsf15e]

When your left mag needs changed or OH’d, switch it for a Surefly E mag.  Eliminates the SOS.  Also, it just works better than a mag and requires less planned maintenance.  I’ve had mine on for 2+ years and 200 hours.  It’s great.

[Ragsf15e]

2 hours ago, 0TreeLemur said:

Perhaps "could" is a better recommendation.  Some say that Surefly introduces a few potential issues.

I disagree.  Not to say there haven’t been some issues, but I feel like they’ve been addressed.  The one I’m thinking of is the issue with 24v planes where the voltage was fluctuating and causing the SF to reset.  They have an updated model that fixed that.  
 

Are there other Issues?  Mine has been great, but that’s only one data point.

[DXB]

1 hour ago, Ragsf15e said:

I disagree.  Not to say there haven’t been some issues, but I feel like they’ve been addressed.  The one I’m thinking of is the issue with 24v planes where the voltage was fluctuating and causing the SF to reset.  They have an updated model that fixed that.  
 

Are there other Issues?  Mine has been great, but that’s only one data point.

Yeah this is probably the way to go for an IO360 in the modern world rather than fuss over the SOS system. The benefits far outweigh the potential issues. If one wants to make the replacement as similar as possible to the mag, just set it to fixed timing when installing.

[Guest]

Installation of a Surefly, means also replacing the left ignition harness with a new one.

[DXB]

On 1/21/2023 at 5:12 PM, M20Doc said:

Installation of a Surefly, means also replacing the left ignition harness with a new one.

You need a Slick harness, so only if you are replacing a Bendix mag - I wasn't sure OP mentioned mag type?

[802flyer]

I have the SlickStart unit and it works well. But I'd still offer another vote for the SureFly mag replacement instead of continuing to futz with an oldschool SOS module or spending money on the SlickStart.

[jamesm]

Check  and make sure that your ignition circuit breaker (if original) has not gone bad or gone intermittent on you.

Years ago I had  the original ignition/cigar CB go intermittent on me. I took me a while to find it since Cigar lighter was on same circuit. I had written off that couldn't be a CB since I had little faith in Cigarette connector connection but as it turned out it really was the CB. 

Hope this helps,

James '67C

[Shadrach]

On 1/20/2023 at 5:32 PM, druidjaidan said:

When we first bought out bird (7ish years ago), the first thing that we discovered broken on my M20F right after we bought it was the SOS system. We didn't know how to recognize it (kicking back when starting), but it was failed when we picked it up. That turned out to be water ingress from a leaky windshield while the plane sat on a ramp in California while title issues were resolved.

A new SOS and resealed windshield later and we were on our way.  This lasted a couple years. We pick up the plane for annual and immediately notice the kick back and lack of buzzing. SOS issues again with a 2 yr old part.  Swap out the part for a used working one so we could get home. This worked for another year or so before more water found it's way into the SOS, no leaky windshield this time, but also no good answer for how water got in at all.  The mechanic (a different one local to my field) made a minor modification this time and drilled a few small holes in the bottom of the SOS case. I don't think it was replaced this time, but I don't recall.

Fast forward to the past year we pick up the plane from a long annual due to major engine maintenance and it won't start. No sound from the SOS. The whole picking up the plane to a failed SOS is getting really fucking old by this time. Mechanic pulls the SOS and bench tests it.  Failed. Takes it apart and cleans up the contacts, and other basic things, then throws a 12v power supply at it and it buzzes nicely. 

That gets me through to now.  It's been winter here and a long vacation away means I haven't flown in going on 2 months. I go out and the SOS has failed again.  We've replaced this thing almost as often as the oil and it just won't stay working.  We're stuck outside due to the combination of high cost (with the cost of hangars here we could replace the SOS every couple months and still break even) and a long wait list (4-5 years last I checked).

Anyone have any thoughts on how to improve the reliability here? This POS glorified solenoid has caused me way too many issues. 

Wow...my plane has the same SOS box that it was delivered with in July of 67. It's has served reliably for 1000s of starts over 55 years.  If only starters were so robust.

[Guest]

22 minutes ago, Shadrach said:

Wow...my plane has had the same SOS box that it was delivered with in July of 67. It's has served reliably for 1000s of starts over 55 years.  If only starters were so robust.

You can adjust them if needed and buy parts to fix them if needed.

[PT20J]

On 1/21/2023 at 10:39 AM, Ragsf15e said:

Are there other Issues?  Mine has been great, but that’s only one data point.

The early units had a long reboot time so when doing mag checks with Bendix mag switches that momentarily turn off both mags when switching between positions the SureFly would shut down long enough to cause a backfire. I believe that they fixed that at the same time that they fixed the 28V voltage spike shutdown problem. The problem is that that they never recalled these so you have to somehow make sure when you order one that you are not getting one that is old stock. Since the older units only had the voltage spike shutdown problem on 28V systems, it seems for a while at least that they were shipping the old stock to all the 14V orders.

Skip

[Ragsf15e]

1 minute ago, PT20J said:

The early units had a long reboot time so when doing mag checks with Bendix mag switches that momentarily turn off both mags when switching between positions the SureFly would shut down long enough to cause a backfire. I believe that they fixed that at the same time that they fixed the 28V voltage spike shutdown problem. The problem is that that they never recalled these so you have to somehow make sure when you order one that you are not getting one that is old stock. Since the older units only had the voltage spike shutdown problem on 28V systems, it seems for a while at least that they were shipping the old stock to all the 14V orders.

Skip

Yeah mine has the longer reboot time but it hasn’t been a problem.  Doing a normal preflight mag check doesn’t cause a backfire.  It does “skip” (no pun) as you go from R back to Both, but no backfire.  

I did an airborne full power mag check after I got it… that did cause a backfire.  I guess it was the higher power?  Since then, if I do an airborne mag check, I reduce power before switching back through.  That works fine.

Anyway, on a 14v system, even the old one seems ok to me.  I’ve been happy with it.

[carusoam]

There is an SOS manual around here somewhere if that would help…

Best regards,

-a-

[DXB]

On 1/23/2023 at 9:04 PM, Ragsf15e said:

Yeah mine has the longer reboot time but it hasn’t been a problem.  Doing a normal preflight mag check doesn’t cause a backfire.  It does “skip” (no pun) as you go from R back to Both, but no backfire.  

I did an airborne full power mag check after I got it… that did cause a backfire.  I guess it was the higher power?  Since then, if I do an airborne mag check, I reduce power before switching back through.  That works fine.

Anyway, on a 14v system, even the old one seems ok to me.  I’ve been happy with it.

I quit doing in flight mag checks after I got mine put in for this reason.  One option is to pull the mixture briefly before switching back, but that's not something I enjoy.  Good idea to simply reduce power.  I would note that even at standard runup power I sometimes get a faint backfire sound.  I should probably do the runups lean rather than full rich per POH. 

[Ragsf15e]

2 hours ago, DXB said:

I quit doing in flight mag checks after I got mine put in for this reason.  One option is to pull the mixture briefly before switching back, but that's not something I enjoy.  Good idea to simply reduce power.  I would note that even at standard runup power I sometimes get a faint backfire sound.  I should probably do the runups lean rather than full rich per POH. 

I do my standard runup check lean, so maybe that’s why?  I don’t have a great technique, but somewhere between taxi lean (which is really lean) and rich.  It just sounds like a quick pause switching through.  

[Mooneymite]

On 1/23/2023 at 8:45 PM, M20Doc said:

You can adjust them if needed and buy parts to fix them if needed.

Absolutely.  Years ago when my SOS was causing starting problems, a set of points and the capacitor, were $13....simple, simple installarion/repair.  Miraculous results!