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Pre-Flight - Drain Gascolator


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10 hours ago, Skates97 said:

Thanks again for all the feedback. I will look for the 1976 version of the POH. I see a 1970 version in the download section. Does anyone have a digital copy of the 1976 POH? If not I'll do some searching tomorrow. 

This fabled '76 POH has eluded me as well.  The 70 POH I've seen is no better than my bare bones '68.  It would be nice to have more detailed performance charts in particular.

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33 minutes ago, DXB said:

This fabled '76 POH has eluded me as well.  The 70 POH I've seen is no better than my bare bones '68.  It would be nice to have more detailed performance charts in particular.

I was not able to find a free download, but I did find where you can purchase it as an $8 download. Much more detailed than the 1965 version I have.

https://www.eflightmanuals.com/ITEM_EFM/SDETAIL_EFM.asp?mID=4839

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So for my Landing gear actuator I found information on a tractor forum.   Is this the same glass bowl the older Cs have?   Like off a Ford 8N tractor?
https://www.amazon.com/Tisco-2NAA9155B-Sediment-Bowl-Assembly/dp/B00CYZFQOE


Ah, the famous glass bowl! I remember that bowl on my 1952 8N. Loved that tractor. Would still have it if I didn't give it to my brother.


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8 hours ago, Bob - S50 said:

 

1.  I sump the tanks first.  If there happened to be water in the tanks and I did the gascolator first, I would introduce water into the line between the tank and the gascolator.

 

Which is why the POH walk around process should not be followed in order!

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Since I bought my M20C I have been draining the gascolator first and then the fuel tanks. The explanation I was given was that the gascolator was the lowest point in the fuel system and if there was water in it would accumulate at that point. By draining gas water would be eliminated...


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Just now, Oscar Avalle said:

Since I bought my M20C I have been draining the gascolator first and then the fuel tanks. The explanation I was given was that the gascolator was the lowest point in the fuel system and if there was water in it would accumulate at that point. By draining gas water would be eliminated...


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The problem is if water accumulates in the tanks while sitting due to something like leaking gas caps. The water may not have made it to the gascolator yet. If you drain the gascolator first you migh pull water from the tanks into the lines. It's better to start higher in the system (the tanks) and make sure those are clear before moving to the lowest point (gascolator). 

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On 2/21/2017 at 0:51 PM, N201MKTurbo said:

You can drain it from outside with your fuel sampler.

Yes you can BUT it does not reseal very well if opened from that direction.  I used to do that, then one day it declined to reseal at all and I had to frantically get a 5 gallon bucket to catch the flow while I tried to convince the gascolater to reseal. It dumped two or three gallons on the tarmac to the displeasure of the FBO.   It reseals fine if you pull the ring, but I think the seal disc gets tilted if you do it from the outside, and it sometimes fails to seal.

I don't pull mine at all anymore.  It is not legal to simply dump fuel on the ground, as it once was when these systems were installed.  To be legal, you have to go find a bucket or pan, put it under the gascolator (don't miss), and then find a place such as a maintenance facility where you can dispose of the fuel after.  Most will have a bucket for the purpose.  But what a pain!  I just leave it alone.  Maybe once a year I will use it just to clear anything that has collected.

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1 hour ago, jlunseth said:

Yes you can BUT it does not reseal very well if opened from that direction.  I used to do that, then one day it declined to reseal at all and I had to frantically get a 5 gallon bucket to catch the flow while I tried to convince the gascolater to reseal. It dumped two or three gallons on the tarmac to the displeasure of the FBO.   It reseals fine if you pull the ring, but I think the seal disc gets tilted if you do it from the outside, and it sometimes fails to seal.

I don't pull mine at all anymore.  It is not legal to simply dump fuel on the ground, as it once was when these systems were installed.  To be legal, you have to go find a bucket or pan, put it under the gascolator (don't miss), and then find a place such as a maintenance facility where you can dispose of the fuel after.  Most will have a bucket for the purpose.  But what a pain!  I just leave it alone.  Maybe once a year I will use it just to clear anything that has collected.

Shutting off the fuel selector would've stopped the flow. 

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The problem is if water accumulates in the tanks while sitting due to something like leaking gas caps. The water may not have made it to the gascolator yet. If you drain the gascolator first you migh pull water from the tanks into the lines. It's better to start higher in the system (the tanks) and make sure those are clear before moving to the lowest point (gascolator). 

Good point, the angle you are sharing. I will change my procedure.

Oscar


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11 hours ago, mooniac15u said:

The problem is if water accumulates in the tanks while sitting due to something like leaking gas caps. The water may not have made it to the gascolator yet. If you drain the gascolator first you migh pull water from the tanks into the lines. It's better to start higher in the system (the tanks) and make sure those are clear before moving to the lowest point (gascolator). 

Makes sense.  I imagine one could skip the gascolator much of the time but maybe it also functions to dump any sediment in it so the gascolator screen stays unconstricted?   

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23 hours ago, Skates97 said:

I was not able to find a free download, but I did find where you can purchase it as an $8 download. Much more detailed than the 1965 version I have.

https://www.eflightmanuals.com/ITEM_EFM/SDETAIL_EFM.asp?mID=4839

Thanks!  I downloaded the M20C '76-'78 and uploaded here in case anyone else wants it.  At quick glance the performance charts do look much better! These are getting printed out, laminated, and going in the flight bag.

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1 hour ago, mooniac15u said:

Shutting off the fuel selector would've stopped the flow. 

When you are under the plane sumping and you are getting full fuel flow onto the ground, you lose a gallon just in the time it takes to get out from under the plane and into the cockpit.  Then you need to fix what just happened because you can't fly with the valve closed, so you have to try things and open the valve to see if it worked, and if you do that you have to get out of the plane and look, and then if you find out it didn't the fuel is flowing full bore onto the ground again.  That is why you need the bucket.  What fixed it was to whack the underside of the sump cup firmly with an open palm, with the sump cup rod engaged in the gascolator.  I have no interest in attempting to use the sump cup on the gascolator again.  It works fine on the wing sumps, but not the gascolator.

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It's sort of like pulling the parking brake in an automatic trans car that never gets the brake pulled except the schmuck at the car wash who pulls it (on a level surface too, the jackass).  Then the calipers freeze shut and wear your pads, warp your discs, etc.  

I don't pull the drain at the selectors but maybe once every quarter.  When I do it I put a glass vase under it, drain a little from each tank, then look for junk in it similar to the sump cup.

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On 2/22/2017 at 9:06 AM, mike_elliott said:

I personally would not recommend doing this, as it can potentially damage the plunger that seats causing a slight leak. A better practice is to pull the gascolator ring for each tank when you begin the preflight with doing the interior work as noted in the poh first., then doing the exterior tasks. You will know if it is still running out. As another poster said, it is better to sump the wings prior to pulling the gascolator ring, however.

The purpose of pulling the gascolator ring is to remove any sediment that may be accumulating prior to it plugging up you carb jets or finger screen in the servo, like what was happening in another thread here recently that the op is now trying to sell the plane because of. Yes, there is a screen in the vintage gascolators that should be checked at each annual, along with the finger strainer screen in the injected IO360's, but they don't catch everything. 

I fail to see how pulling the ring vs pushing up on the plunger with a sample cup is any different... the only risk I can think of is that the sample cup rod scratches the piston in the gascolator.  When I disassemble the gascolator, it contains the piston (which the ring is directly attached to from above) and an o-ring that fits into a groove on the bottom of that piston, as well as a micro-screen and a larger o-ring that seals the entire unit.  Spruce sells the micro screens for something like $1.00.  And the o-rings, too are very cheap.  If the gascolator is leaking, or doesn't "quickly" return to a non-leaking state- just replace the small o-ring (it's probably worn from use).  The piston in the gascolator has a small groove in the bottom that sure seems like it was designed for a sample cup rod- and there is no unique features to that piston that would preclude pushing, vs pulling on the ring so far as I can tell. 

The one compelling reason to pull on the ring, vs pushing, is that you can more easily switch tanks and know which one you have selected from in the cockpit.  And it ensures that you sump both prior to draining the gascolator.

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6 hours ago, M016576 said:

I fail to see how pulling the ring vs pushing up on the plunger with a sample cup is any different... the only risk I can think of is that the sample cup rod scratches the piston in the gascolator.  When I disassemble the gascolator, it contains the piston (which the ring is directly attached to from above) and an o-ring that fits into a groove on the bottom of that piston, as well as a micro-screen and a larger o-ring that seals the entire unit.  Spruce sells the micro screens for something like $1.00.  And the o-rings, too are very cheap.  If the gascolator is leaking, or doesn't "quickly" return to a non-leaking state- just replace the small o-ring (it's probably worn from use).  The piston in the gascolator has a small groove in the bottom that sure seems like it was designed for a sample cup rod- and there is no unique features to that piston that would preclude pushing, vs pulling on the ring so far as I can tell. 

The one compelling reason to pull on the ring, vs pushing, is that you can more easily switch tanks and know which one you have selected from in the cockpit.  And it ensures that you sump both prior to draining the gascolator.

What happens is the rod from the sampling cup nicks the o-ring around the piston as it's used to push the piston up. Once nicked, you have a leak and many of have found themselves grounded till they replace that small o-ring in the gascolator. You might get away with it a 100 times without damaging the o-ring and then when you have an important departure time to meet end up grounding yourself nicking the o-ring.

I live in CA were we have the most stringent rules but I continue to drain the gascolator the first flight of the day and sump the tanks before every flight - regardless whether or not I take on gas. I am just not going to be that pilot that took off and missed the last chance to catch an issue with his fuel whether it be water or contamination from vandalism. It take all of a couple minutes and enables me to be checking the security of the gear, brakes and landing gear doors etc. while I do it.  Yes the chances are very slim, but the consequences are to severe IMO to pass up the final opportunity to prevent a power loss on departure.

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12 hours ago, kortopates said:

What happens is the rod from the sampling cup nicks the o-ring around the piston as it's used to push the piston up. Once nicked, you have a leak and many of have found themselves grounded till they replace that small o-ring in the gascolator. You might get away with it a 100 times without damaging the o-ring and then when you have an important departure time to meet end up grounding yourself nicking the o-ring.

I live in CA were we have the most stringent rules but I continue to drain the gascolator the first flight of the day and sump the tanks before every flight - regardless whether or not I take on gas. I am just not going to be that pilot that took off and missed the last chance to catch an issue with his fuel whether it be water or contamination from vandalism. It take all of a couple minutes and enables me to be checking the security of the gear, brakes and landing gear doors etc. while I do it.  Yes the chances are very slim, but the consequences are to severe IMO to pass up the final opportunity to prevent a power loss on departure.

Very valid

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The main purpose for pulling the gascolator ring is to back flush the screen inside it to remove trash.  I think there was a forced  Mooney landing a few years ago due to engine problems and the cause was determined to be a plugged gascolator screen. Failing fuel tank lining or contaminated fuel can plug this screen and a back flush before every flight is a good idea.  

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4 minutes ago, Gary0747 said:

The main purpose for pulling the gascolator ring is to back flush the screen inside it to remove trash.  I think there was a forced  Mooney landing a few years ago due to engine problems and the cause was determined to be a plugged gascolator screen. Failing fuel tank lining or contaminated fuel can plug this screen and a back flush before every flight is a good idea.  

If that is the case, then is there any reason to drain, switch tanks, and drain again? Wouldn't just flushing it from one of the tanks have the desired result of clearing the screen? Just trying to understand...

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One of my worries related to this is a leaking fiel drain valve when sumping the tanks. I have considered just carrying an extra valve in with the tool kit but changing must mean an avgas shower! I guess that's better than being stranded somewhere. 

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One of my worries related to this is a leaking fiel drain valve when sumping the tanks. I have considered just carrying an extra valve in with the tool kit but changing must mean an avgas shower! I guess that's better than being stranded somewhere. 

Probably a good idea, I've had then leak because of debris stuck in them, but repeated drainings have cleared it. Anyone know exact drain used, they look like flush mounted curtis but don't know thread size?
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