Guitarmaster Posted January 5, 2015 Report Posted January 5, 2015 Hey guys. The left wing sump has something wrong with it that makes it very difficult to close once the fuel is sumped. If I jack with it enough, it will eventually close, after dousing me with 100LL of course. This is my question, does anybody know offhand what the size and pipe thread is for the sump on a '75F? I just read in " sport aviation" how to solve this problem without draining the tanks and I am super happy about that! I can look it up the size, but I thought someone would have the knowledge easily accessible. Thanks! Matt Sent from my iPad using Tapatalk Quote
carusoam Posted January 5, 2015 Report Posted January 5, 2015 Matt, Taking the old one out and putting a new one in its place is pretty easy. Use caution, over torquing will break it in half. Just like my mechanic told me it would... Some very flammable liquid will be spilled. Be smart, have plan B ready to go... José (Piloto) had given an explanation of what the best drain design was in another thread. Best design included holes at the proper height to drain water most completely... Best regards, -a- Quote
Guest Posted January 5, 2015 Report Posted January 5, 2015 You need a new F391-53S valve. The change can be made with fuel int the tank, however as noted above 100LL is highly flammable. Clarence Quote
Sabremech Posted January 6, 2015 Report Posted January 6, 2015 Matt, Taking the old one out and putting a new one in its place is pretty easy. Use caution, over torquing will break it in half. Just like my mechanic told me it would... Some very flammable liquid will be spilled. Be smart, have plan B ready to go... José (Piloto) had given an explanation of what the best drain design was in another thread. Best design included holes at the proper height to drain water most completely... Best regards, -a-[/quote M20Doc is giving you the correct part number for your aircraft. Jose's (Piloto) advice is not accurate. Quote
Marauder Posted January 6, 2015 Report Posted January 6, 2015 Are your tanks original? On my 1975 F, I had these rubber worms that were plugging up the drains. Possibley you got one of them stuck in it. Quote
M016576 Posted January 6, 2015 Report Posted January 6, 2015 Matt, Taking the old one out and putting a new one in its place is pretty easy. Use caution, over torquing will break it in half. Just like my mechanic told me it would... Some very flammable liquid will be spilled. Be smart, have plan B ready to go... José (Piloto) had given an explanation of what the best drain design was in another thread. Best design included holes at the proper height to drain water most completely... Best regards, -a- That's no joke about the torque specs and the valve shearing... That torque spec printed on the package is in INCH-lbs.... Not foot-lbs... Quote
N201MKTurbo Posted January 6, 2015 Report Posted January 6, 2015 Put a bucket under the drain. Unscrew it and put your finger on the hole. Take your finger off of the hole and screw in the new valve. If they are the same as the ones in my 201 that is. They have an o-ring seal, screw them in till they stop leaking and just a little bit more. My 67 F had riveted in drain valves that worked perfect when I sold it. 3 Quote
47U Posted January 6, 2015 Report Posted January 6, 2015 I've got one of each. The original riveted drain on the left and the SB modified on the right. I changed the right side drain last annual because of a persistent blue stain. I opted to drain the tank completely when I took the leaky one out. After I put the new one in, I added a few gallons and let that drain out of the tank selector valve B-nut into a bucket until it stopped. I figured what was left in the tank was "unusable fuel." I refilled the tank in 5 gallon increments to calibrate my dipstick with what is useable fuel. With only 48 total gallons on board, I wanted to have another data point. Quote
The-sky-captain Posted January 6, 2015 Report Posted January 6, 2015 I had the same issue a couple times and ACF 50 would clear it up. It happened about once a year for a couple years so I just replaced them at last annual. In a pinch give the ACF a try. Quote
Guitarmaster Posted January 6, 2015 Author Report Posted January 6, 2015 Thanks a bunch guys. I love this board! She is going for her annual this week. Fingers crossed nothing major. . I am going to do a field approval for the LED nav lights at the same time. I will let you all know how that goes. BTW... who's going to Airventure this year? Would be great to meet you guys in person sometime. I missed last year, but would love to go with a bunch of other Mooneys! Quote
Guitarmaster Posted January 6, 2015 Author Report Posted January 6, 2015 Are your tanks original? On my 1975 F, I had these rubber worms that were plugging up the drains. Possibley you got one of them stuck in it. I thought about that and I looked very closely ever since you made mention of that the first time. I have seen no indications of any worms in the gas tank though. Quote
DrBill Posted January 10, 2015 Report Posted January 10, 2015 I've got one of each. The original riveted drain on the left and the SB modified on the right. I changed the right side drain last annual because of a persistent blue stain. I opted to drain the tank completely when I took the leaky one out. After I put the new one in, I added a few gallons and let that drain out of the tank selector valve B-nut into a bucket until it stopped. I figured what was left in the tank was "unusable fuel." I refilled the tank in 5 gallon increments to calibrate my dipstick with what is useable fuel. With only 48 total gallons on board, I wanted to have another data point. Be careful.. That is NOT your really useable fuel.. Only for straight and level flight.. On approach if you ever need to slip it in due to crosswinds or drop some altitude, your useable fuel will be LESS ! BTW i did the same thing. BILL Quote
N601RX Posted January 10, 2015 Report Posted January 10, 2015 I've had the pickup suck air with 8-9 gallons in the tank during a hard slip. Not a good feeling to hear the engine sputter 200 ft off the ground. 1 Quote
47U Posted January 10, 2015 Report Posted January 10, 2015 That's good to know! The possiblility of slipping and unporting a tank that's 1/3 full is something I'd not heard before, but will remember. With only 48 total on board, my fuel strategy will continue to be conservative. Quote
N201MKTurbo Posted January 10, 2015 Report Posted January 10, 2015 You just have to remember which tank is selected and put that wing up. Or, just land with more fuel... 1 Quote
Guitarmaster Posted January 10, 2015 Author Report Posted January 10, 2015 It turns out there is a defect in the sump itself. Or something with up with the little Oring and keeps getting caught, letting fuel come out. End result, new sump. 1 Quote
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