How Long Will the Engine Run with Fuel Selector OFF

[Hector]

In the cockpit, there is a "fuel sump drain" with a ring pull on my 1986 M20J.  I have never used it.  It appears to drain the fuel aka a Cessna or Piper out of the tube in the cowling, but I have not worked out how to pull the ring, runaround at high speed to the front plane put a beaker underneath the pipe, run back again, close the pull ring.....you get the gist.

what on earth is it for and how the hell do you test it?

Andrew

It is spring loaded. Just pull up (it takes some force) and hold it for a few seconds. Switch tanks and repeat. You should do this as part of your preflight.

[Guest]

2 hours ago, Hyett6420 said:

In the cockpit, there is a "fuel sump drain" with a ring pull on my 1986 M20J.  I have never used it.  It appears to drain the fuel aka a Cessna or Piper out of the tube in the cowling, but I have not worked out how to pull the ring, runaround at high speed to the front plane put a beaker underneath the pipe, run back again, close the pull ring.....you get the gist.

what on earth is it for and how the hell do you test it?

Andrew

Andrew,

It is the gascolator and main airframe fuel screen.  Your maintainer should be disassembling and cleaning each 100 hours or annual inspection.

Clarence

[Heybluez]

On February 15, 2016 at 5:57 PM, M20F said:

One additional thing I reccomend is turning your fuel off with the engine running at least once.  This will give you an approximate as to what the line holds but also verify the fuel actually shuts off.  I have flown a fair number of planes that the fuel shutoff doesn't fully shut the fuel down.  

The instructor and I did this (on the ground, of course!!) to see how long it would take after I asked the question.  I have a 86 201 and it took about 4-6 seconds.  Not long at all!  Probably why I count to 6 with my hand on the switcher when I switch tanks now.. Just in case so I can switch back if need be. That and watch fuel flow when I do switch.

[Cyril Gibb]

5 hours ago, Hyett6420 said:

In the cockpit, there is a "fuel sump drain" with a ring pull on my 1986 M20J.  I have never used it.  It appears to drain the fuel aka a Cessna or Piper out of the tube in the cowling, but I have not worked out how to pull the ring, runaround at high speed to the front plane put a beaker underneath the pipe, run back again, close the pull ring.....you get the gist.

what on earth is it for and how the hell do you test it?

Andrew

I keep an old tinny cookie sheet in the hangar.  I put it under the gascolator and pull the ring.  You can hear the fuel dribbling on the sheet from the pilot window and check for any water on the cookie sheet when you come back around.

[Shadrach]

6 hours ago, Hyett6420 said:

In the cockpit, there is a "fuel sump drain" with a ring pull on my 1986 M20J.  I have never used it.  It appears to drain the fuel aka a Cessna or Piper out of the tube in the cowling, but I have not worked out how to pull the ring, runaround at high speed to the front plane put a beaker underneath the pipe, run back again, close the pull ring.....you get the gist.

what on earth is it for and how the hell do you test it?

Andrew

Some gascolator so can be operated like a sump from outside the plane. That being said, I am meticulous with my inspection of the fuel system at annual. However, I readily admit that I rarely drain the gascolator. Knowing the configuration of the fuel system, I know that if my tanks have no water present, neither does the gascolator.

[ArtVandelay]

1 hour ago, Cyril Gibb said:

I keep an old tinny cookie sheet in the hangar.  I put it under the gascolator and pull the ring.  You can hear the fuel dribbling on the sheet from the pilot window and check for any water on the cookie sheet when you come back around.

That should never happen if you drain your tanks religiously, have you ever found water?

I just dump it and make sure the fuel stops when I release it.

[Marauder]

The fuel from sump drain was never intended to be caught. It was put there to allow the pilot to do an un-environmentally pull to get any crud and water out of the low point of the system.

Sent from my iPad using Tapatalk

[Cyril Gibb]

1 hour ago, teejayevans said:

That should never happen if you drain your tanks religiously, have you ever found water?

I just dump it and make sure the fuel stops when I release it.

Nope, never.  But I tend to be a belt and suspenders guy.  I've also never found water sumping the tanks, but I still always do it.

[ArtVandelay]

34 minutes ago, Cyril Gibb said:

Nope, never.  But I tend to be a belt and suspenders guy.  I've also never found water sumping the tanks, but I still always do it.

That I've found after fueling, I'm more careful of cleaning the water lying in the groove of the fuel cap.

[blaine beaven]

In my 78J, I have shut the engine off while taxiing by switching to OFF. The purpose was to a) ensure my OFF position worked and see how long it took. It was under 10 seconds.

When I used to fly a 185 I was always told there is enough fuel after the OFF position to start up, run up, taxi, takeoff and get to 100ft before the engine quits

Sent from my iPhone using Tapatalk

[Marauder]

Hi Andrew -- the sump is supposed to be the low point of the fuel system. My POH has it as part of the pre-flight check along with the interior check of stuff. My assumption but it may be in the POH is that after you pull it (like I did for years), you verify during your external walk around. I don't remember if I stopped doing it that way because of the environmental concern or when I had my boost pump changed out, there was a sump that I could now use.

Sent from my iPad using Tapatalk

[carusoam]

Reviewing what l have read...

1) two tanks makes it wise to pull the ring twice, operating the the selector valve in between.

2) catch pan sounds interesting.

3) check for dripping in the event crud gets stuck in the valve.

4) Some people use the fuel sample cup to operate that valve from below, catch and inspect what comes out...

5) I operate the selector valve and pull the ring while being outdoors.

Best regards,

-a-

[Guitarmaster]

Reviewing what l have read...

5) I operate the selector valve and pull the ring while being outdoors.

Best regards,

-a-

You must have some seriously long arms!

[carusoam]

Me and all my Yetti friends are doing it this way....

[Marauder]

Reviewing what l have read... 5) I operate the selector valve and pull the ring while being outdoors.

Best regards,

-a-

You must have some seriously long arms!

If you ever met him in person, you could personally inspect his knuckles calloused by dragging them on the ground.

[Hector]

Reviewing what l have read... 5) I operate the selector valve and pull the ring while being outdoors.

Best regards,

-a-

You must have some seriously long arms!

He needs long arms to properly embrace his ladies

[Seth]

On February 16, 2016 at 11:13 PM, Hector said:

At idle it takes a minute or two for a carbureted M20C. Don't ask how I know.

How do you know and please share your experience?

[Seth]

On February 16, 2016 at 9:38 AM, MyNameIsNobody said:

Also in a 152.  I was training with my 1000 hour 19 year old instructor and when I pulled mixture to cut-off it came off in my hand...He went "I don't know what to do"...I said "I will shut the fuel off".  He smiled and the plane shut down in about a minute.  Also had fuel prime come off while on night flight cross-country...

I had the fuel prime in a 172 come out in flight.  The locking mechanism was worn.  It was a day flight.

-Seth

[Marauder]

On February 16, 2016 at 9:38 AM, MyNameIsNobody said: Also in a 152.  I was training with my 1000 hour 19 year old instructor and when I pulled mixture to cut-off it came off in my hand...He went "I don't know what to do"...I said "I will shut the fuel off".  He smiled and the plane shut down in about a minute.  Also had fuel prime come off while on night flight cross-country...

I had the fuel prime in a 172 come out in flight.  The locking mechanism was worn.  It was a day flight.

-Seth

Ever have one leak, that adds a twist (pun intended) to the situation.

[Seth]

On two separate instances I had a clogged fuel injector in my former F model that presented itself dour ring cross county trips.

Once it was actually dirt.  Once it was what can only be described as paint chips.

I always did the left sump right sump from the cockpit.  My MSC said to count to five on each tank to ensure a good amount of fuel and whatever debris may be in there is flushed prior to start up.

I've never had an issue with the Missile but also drain the gasocolector right and left each time before start up.  I do not use a trey or cup to catch it and inspect.

I have never had water in the tanks of either of my Mooney aircraft.

-Seth

 

 

 

[Seth]

4 minutes ago, Marauder said:

Ever have one leak, that adds a twist (pun intended) to the situation.

That would be REALLY bad and yes, quite a . . . Twist

[carusoam]

3 hours ago, Seth said:

How do you know and please share your experience?

Not sure how Hector found out, but...

I tested my C's both position during a demo flight.  I taxied quite a distance to find that there wasn't a both position in a Mooney. 

There are supposed to be detents that would have given a hint.  But there weren't any of those either.

Best regards,

-a-

[Steve Dietrich]

I don't think "BOTH" works with low wings..........   Also the lateral CG is more important with the low wing so the need to balance the fuel load is greater .

 

I don't think the engine will run very long at all (assuming it is injected and producing power )

 

Edited April 4, 2016 by Steve Dietrich

[carusoam]

Steve, you could have told me that 15 years ago. . Nothing but C152 hours prior.  'Both' seamed like a good idea.

What I really learned, was to share my ideas with the other pilot before acting on them.  Since I hadn't gained an hour in Mooneys yet.

My M20C was a thing of beauty,  it did straight and level with precision.  Steering, using weight shift technique was possible.  We were able to follow a 'magenta' line on a portable GPS.  Black LCD on G186...

Best regards,

-a-

[Yetti]

To check the Gas colater screen I have a piece of plastic tubing that is a little bit longer than plane to ground.  The tubing is put in an old Mason Jar.  Check both tanks from the cockpit.  Get out and inspect fuel then toss gas into the engine on the tug.

Disparaging remarks about the Tribal Yetti have been ignored due to the mythical status of the said creature

Edited April 5, 2016 by Yetti