Groundhog Posted April 28, 2021 Report Posted April 28, 2021 I had a slow fuel drain on one side when I went to go pick my 1978 J up from annual/prebuy. I had the shop look at it before I took the plane, because I was concerned it could be a venting issue. They said it was fine, just a slow drain. Later I had a different mechanic come look at it and had him change the valve. It was still slow even with a brand new valve. Anyone have this same experience? Quote
Guest Posted April 28, 2021 Report Posted April 28, 2021 It’s possible that the small holes in the nut plate inside the tank are partially blocked. Clarence Quote
Groundhog Posted April 28, 2021 Author Report Posted April 28, 2021 Thanks Clarence. Is there any way to clear that out, short of opening up the tank? Quote
N201MKTurbo Posted April 28, 2021 Report Posted April 28, 2021 What Doc said. If you had tank work done, it probably has sealant blocking the hole. If not, there is probably debris blocking the hole. If you drain the tank you may be able open it up from the bottom with the valve removed, if that doesn't work go in through the fuel level sender hole. If it is sealant, pokeing something through doesn't always work. The sealant will snap back and close the hole after the poker is removed. You have to somehow remove a little bit of sealant. 2 Quote
carusoam Posted April 28, 2021 Report Posted April 28, 2021 Take the required time to clear it correctly... water intrusion in the fuel system can have crummy results... PP thoughts and motivational speech only... Best regards, -a- Quote
PT20J Posted April 28, 2021 Report Posted April 28, 2021 You might also check to see if the drain has been replaced. I replaced a leaking MDI F391-53S with a SAF-AIR SA53S and the SAF-AIR part has a stiffer spring and drains more slowly than the original MDI drain. It’s not really slow, but it is different. Skip 1 Quote
Groundhog Posted April 28, 2021 Author Report Posted April 28, 2021 I had both drains replaced with the SAF-AIR ones, and I did notice they were both a little different in draining than before. But the one side is still slower. I can get plenty of fuel out for a sample, it just takes longer than the other side. I’m wondering if I should even worry about it since I can take a full sample with a little patience. Quote
Guest Posted April 28, 2021 Report Posted April 28, 2021 With the tank drained it might be worth trying to poke a length of safety wire through the opening to clear it. I certainly wouldn’t open the tank if it’s still draining. Clarence Quote
EricJ Posted April 29, 2021 Report Posted April 29, 2021 I've noticed a difference between types of drain plugs. I had two of the MDI F391-53S plugs in my airplane and they both flowed pretty fast. One of them got sticky, so I replaced it with an equivalent Saf-Air and it doesn't flow nearly as much. The other MDI recently got a little weepy (wasn't the plug, it turns out), and I replaced it with a Saf-Air and the same thing happened; the Saf-Air doesn't flow nearly as much as the MDIs did. Quote
A64Pilot Posted April 29, 2021 Report Posted April 29, 2021 (edited) So long as you get more than a trickle I wouldn’t worry about it, it’s just a drain and has no other function Just be glad it doesn’t stick partially open, those can be a pain. Edited April 29, 2021 by A64Pilot Quote
carusoam Posted April 29, 2021 Report Posted April 29, 2021 When one side drains slower than the other... Be on the look out for dirt in the drain holes or sealant... Not everyone knows of the tiny holes where fuel flows through in Mooney tanks... If there is sealant in the sump drain holes... check the rib holes too... lots of useable fuel can become unusable when the rib holes get blocked... PP thoughts only, not a mechanic... Best regards, -a- Quote
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