Engine trouble on takeoff-I was lucky.

[ArtVandelay]

Took a pic of the diaphragm that came out of mine:

What’s it made of? To my untrained eye, looks pretty good.

[Mooney in Oz]

On 9/6/2018 at 2:04 AM, jma201 said:

However, there is also a time TBO of twelve years regardless of engine hours.

This issue should be subject to an AD to be done every 12 years or engine TBO, whichever occurs first.

I had no idea about this until reading this thread.

Thanks for sharing @jma201 and to the other MS'er's their experiences.  It is vitally important we know about issues like this. 

[M20F-1968]

FYI:  

It took me over 10 years to rebuild my aircraft.  The fuel system was rebuilt back in 2003 but the plane did not start flying regularly until 2014.  At that time, I took the fuel servo system out and had it rebuilt and put in a new fuel pump (because of the 10 year limit).  When rebuilt in 2014, the rebuilder found a diaphragm in the fuel servo installed that had the letters signifying that it was subject to an AD, prior to 2003.  The diaphragm was either replaced with a new diaphragm that had an AD, or it was never replaced at all.  (The engine was rebuilt in 1983 to new specs but was not run, so mybe he decided it looked good and he could get away with it).  The engine went to PennYan in 2003 and the fuel servo went to a local Dallas shop in the same year.    

The moral of the story, better to send your accessories out to a shop of your choice (not one selected by an A&P), or better yet, let the engine rebuilder address the accessories as well.  Too much can go on behind your back.

John Breda

[MBDiagMan]

Thanks for posting!

This will be a great topic to bring up at the MAXMaintenance seminar next month.

Glad you’re okay jma!

[chrixxer]

On 9/5/2018 at 2:45 PM, chrixxer said:

Not mine, at least, not exactly. On mine, the fuel servo probably wasn't bad - I'll have to dig through the logs but IIRC the fuel servo was well within calendar and time TBO - but I replaced it anyway, abundance of caution.

@carusoam - my fuel servo was overhauled by Western Skyways 8/7/2010 at 3600 on the tach; it failed (if it failed) due to FOD on 7/9/2018 at 4020, so, well within TBO.

But TBH, I didn't know there was a TBO on the fuel servo. Big things - prop, engine, etc. - sure, but ... Where would you find a list of such things? What all would be on it? Mags? Fuel pump(s)? Landing gear motor(s)? Some of these will be ADs / SBs I imagine ... 

I'm building a database to manage plane ownership (free to Mooney pilots, on a sliding scale up to $949 for Cirrus SR22 owners , if/when it ever becomes something functional and polished enough to be usable), and TBH I'm realizing how much I don't know... 

[carusoam]

Chrix,

Similar to...

• carburetors
• governors
• mags
• starters
• alternators
• oil system, oil cooler, pressure valve, vernatherm...
• turbo, pressure controller, intercooler...
• prop and seals...

If its a system attached to the engine, it is going to have a limited life...

Some get statistics applied to them like the mags... 500hrs...

You would want to know where on the time line each one is... years and hours...

In lieu of that... going factory OH and replacing all the systems may make (some) sense...

See if @M20Doc has a list subsystem TBOs or guidelines that some customers like to follow....?

Early in my flying experience, simple things drained the Aviation budget completely...

Nothing more simple than a pair of kids...  

PP thoughts, not a mechanic....

Best regards,

-a-

[Guest]

From Precision Airmotive, 12 year TBO

http://www.precisionairmotive.com/Publications/PRS-97 Rev2.pdf

Clarence

[ArtVandelay]

From Precision Airmotive, 12 year TBO
http://www.precisionairmotive.com/Publications/PRS-97 Rev2.pdf
Clarence

Couple of caveats:
It’s in their best interest to have you overhaul early and often.
Sometime in the mid eighties they changed to fluorosilicone which doesn’t degrade with age.
Lycoming also recommends a 12 year overhaul.

If I had a servo that’s older than 1986, I definitely would overhaul, but 2006? No way!

[jetdriven]

On 9/8/2018 at 1:31 PM, EricJ said:

Took a pic of the diaphragm that came out of mine:

 

That looks like water puddling there, see the corrosion on the aluminum part in the middle?

[Guest]

3 hours ago, teejayevans said:

Couple of caveats:
It’s in their best interest to have you overhaul early and often.
Sometime in the mid eighties they changed to fluorosilicone which doesn’t degrade with age.
Lycoming also recommends a 12 year overhaul.

If I had a servo that’s older than 1986, I definitely would overhaul, but 2006? No way!

Not saying it is mandatory.  I just dig out the links for other to consider.

Clarence

[EricJ]

7 hours ago, jetdriven said:

That looks like water puddling there, see the corrosion on the aluminum part in the middle?

That was my assessment, too.   Whatever it was, I don't think it helped the function or performance of the device.

[jetdriven]

With water contamination, all bets are off. TBO,  careful preflights,  hours and years dont matter.

[Piloto]

I had the same engine out experience on take off on my 1982 M20J. It was caused by undrained water due to a clogged bottom drain holes on the fuel drain adapter plate. As the plane accelerates the undrained water is displaced toward the back fuel pick up location causing the engine to ingest water. The only way to drain all the water is to remove the drain valve. No matter how much run up testing you will not experience the symptoms until the plane accelerates. I replaced the drain valves for the  F-391-72 which has the drain holes directly exposed to the tank and are not subject to debris clogging. No problem since.

José 

Edited September 15, 2018 by Piloto

[Andy95W]

Just so everybody knows, the drain valve referenced by José above is not correct so use it at your own risk.  Per the M20J Parts Manual, the proper drain valve is the F-391-53S.  For Pre-M20J, per SB M20-188, the proper drain valve is also the F-391-53S. 

BTW, this is noted by both Don Maxwell and Clarence (M20Doc) and has been much discussed in the past.  

[Piloto]

2 hours ago, Andy95W said:

Just so everybody knows, the drain valve referenced by José above is not correct so use it at your own risk.  Per the M20J Parts Manual, the proper drain valve is the F-391-53S.  For Pre-M20J, per SB M20-188, the proper drain valve is also the F-391-53S. 

BTW, this is noted by both Don Maxwell and Clarence (M20Doc) and has been much discussed in the past.  

The F-391-53S works well on a new clean Mooneys. But as the tanks ages sealant and fuel debris end up clogging the drain adapter holes. Proper cleaning of these drain holes requires opening the tanks at every annual and carefully removing the debris. Not to mention the possibility of fuel stains after doing this. BTW the Monroy Long Range tanks and all Cessnas uses the F-391-72 and are FAA STC approved.

José 

Edited September 15, 2018 by Piloto

[jetdriven]

9 hours ago, Piloto said:

I had the same engine out experience on take off on my 1982 M20J. It was caused by undrained water due to a clogged bottom drain holes on the fuel drain adapter plate. As the plane accelerates the undrained water is displaced toward the back fuel pick up location causing the engine to ingest water. The only way to drain all the water is to remove the drain valve. No matter how much run up testing you will not experience the symptoms until the plane accelerates. I replaced the drain valves for the  F-391-72 which has the drain holes directly exposed to the tank and are not subject to debris clogging. No problem since.

José 

You must have a lot of water in your tank, because the pick up is a half inch off the bottom of the tank and it’s in the middle of it. I flew with a guy who hadnt sampled his fuel in a while when we filled up and we drained over a quart of water out of each wing and we have been doing stalls steep turns and other maneuvers and everything else, with no issue at all. 

Edited September 15, 2018 by jetdriven

[Guest]

5 hours ago, Piloto said:

The F-391-53S works well on a new clean Mooneys. But as the tanks ages sealant and fuel debris end up clogging the drain adapter holes. Proper cleaning of these drain holes requires opening the tanks at every annual and carefully removing the debris. Not to mention the possibility of fuel stains after doing this. BTW the Monroy Long Range tanks and all Cessnas uses the F-391-72 and are FAA STC approved.

José 

Not to continue beating a dead horse. Why do you continue to give people wrong information?

The F391-72 drain holes are higher than the drain holes in the F391-53S.  Installing this valve in a Mooney drain adapter fitting will allow another 3/8” of water to collect in the bottom of the tank.  

If the drain holes in the adapter fitting are clogged as you suggest, then no fuel will drain with the correct valve installed.  Indicating the need for a repair.

Cessna tanks that I am familiar with have welded aluminum boss on the bottom of the tank, this accepts the F391-72 valve which will now have the valve holes at the bottom of the tank.

Clarence

 

[Guest]

I snapped this picture inside a J model wing today to give an idea of what the wrong drain valve looks like inside the wing.  This is an F391-72 valve screwed into a 1/4” thick aluminum plate which is riveted inside the tank.  The drain holes in the valve are above the plate, therefore water and contaminates can never be fully drained.

Clarence

[carusoam]

If I understand the pic and the description...

the fuel pick-up is below the level of the aluminum block which is clearly below the drain...

Any water entering the tank would never be seen by the person sumping the tank... unless it was gallons of water in the tank...

That seems like an unexpected/unintended lethal combination of maintenance errors.

 

Nice catch Clarence!

Thanks for sharing those details and Pic!

Best regards,

-a-

 

[Guest]

6 hours ago, carusoam said:

If I understand the pic and the description...

the fuel pick-up is below the level of the aluminum block which is clearly below the drain...

Any water entering the tank would never be seen by the person sumping the tank... unless it was gallons of water in the tank...

That seems like an unexpected/unintended lethal combination of maintenance errors.

 

Nice catch Clarence!

Thanks for sharing those details and Pic!

Best regards,

-a-

 

This install is in a Monroy conversion, and in my opinion is a poor design or poor install.  I don’t have all of the paperwork from the installer yet to even confirm if it’s done correctly.

The fuel pick up is above the drain fitting so in theory shouldn’t pick up water unless there is quite a bit in the tank, likely gallons.  In any event by design there will always be at least 3/8” of water and contamination that can’t be drained.  

Clarence

[philiplane]

On 9/6/2018 at 5:28 PM, M20Doc said:

Continental engines don’t have Bendix fuel injection servos like Lycoming engine do, unless you have a Piper Seneca with TSIO-360RB engines.

Continental engines don’t regulate fuel flow based on an airflow diaphragms, they do it based on engine RPM, pump RPM, pump unmetered and metered fuel pressure and mixture plate position.

Clarence

But they do have a diaphragm in the flow divider, made of the same material that fails in the Bendix servos. When the flow divider diaphragm ruptures, it dumps fuel overboard and you may not make enough power to keep flying. The divider is in a worse environment too, sitting on top of a hot engine, and baking at 350 degrees after shut down.

[jetdriven]

On 9/15/2018 at 8:06 PM, M20Doc said:

Not to continue beating a dead horse. Why do you continue to give people wrong information?

The F391-72 drain holes are higher than the drain holes in the F391-53S.  Installing this valve in a Mooney drain adapter fitting will allow another 3/8” of water to collect in the bottom of the tank.  

If the drain holes in the adapter fitting are clogged as you suggest, then no fuel will drain with the correct valve installed.  Indicating the need for a repair.

Cessna tanks that I am familiar with have welded aluminum boss on the bottom of the tank, this accepts the F391-72 valve which will now have the valve holes at the bottom of the tank.

Clarence

 

Dont give in to the fake mechanic giving bad advice and getting people killed.

[jetdriven]

If the divider dumps fuel overboard, then where is the drain line?

[EricJ]

1 hour ago, jetdriven said:

If the divider dumps fuel overboard, then where is the drain line?

If the diaphragm fails the fuel comes out the vent hole in the top of the divider.