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Fuel pump seal leak?


SkipSS

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On the day I picked up my 93 J from annual, I noticed a slow drip of fuel behind my nose wheel and forward of my fuel sump on ground, perhaps a drip every 20 seconds. Shutting off fuel valve stops it.

Turning on boost pump causes it to leak more.

My AP states that it’s the boost pump seal that can leak in cold weather, I’m in Florida and weather has been seasonally colder in recent days.  He states once weather gets warmer in a few days it will stop and its “common” for Mooney’s. 

I’ve not seen any such posting on this “common” problem on Mooneyspace and have only had the airplane 1 year but it never leaked before. 

He says not to replace the pump “till it needs it”, I’m not sure what to believe, I flew it once and it dripped at my destination.  I would understand the issue more if my wing fuel tank was leaking, but this one is closer to the engine.

It appears to be a Weldon A8163B, $1269 from Spruce. I haven’t checked yet whether it’s under an inspection panel or the one piece belly, but believe once I get access to it will be able to see where it’s actually dripping from. My AP is on vacation till second week of January. 

I would appreciate any thoughts on this.

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I’m with Art on this one...   ^^^^

 

My experience with fuel leaks...

That is time to...

1) get OH...

2) get re-sealed...

3) get new pump...

 

 

4) Boost pumps are in line with the mechanical pump...

5) if fuel leaks out while parked, air can leak in while flying... have you seen any funny FF readings? Air bubbles can mess with the FF data...

6) if it is temperature dependent... how bad does it get while at altitude?

7) Typical Mooney pumps have a drain that looks like a hose barb... fuel drips out slowly when the pump Is off...  comes out fast enough a passer by will flag you down when the pump is on...

Mooneys don’t have any normal fuel leaks beyond tiny leaks around rivets on the fuel tank...

PP thoughts only, not a mechanic.

Best regards,

-a-

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If it’s dripping fuel from the vent fitting between the pump body and the electric motor, it needs a repair.  The seal is all that keeps fuel out of the electric motor.

Aeromotors LLC in Wisconsin is a great choice for this.  You can turn off the selector valve, remove the pump and ship it out in time for your A&P to install it on his return.

Clarence

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That’s a shame since that pump should have been pulled at annual and sent out for overhaul. As stated above, about $400. From your description it was already well past the occasional drip.
It’s not trivial to get at since the left nose wheel door will come off with the panel but I’d find a local A&P to take a look before more than a short trip. But he should be able to confirm it’s leaking through the drain without needing to pull the panel.


Sent from my iPhone using Tapatalk

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I didn’t think any fuel leaking from anywhere near the engine is common or normal, I was surprised by mechanic’s reply.  

I did see that the outer side of the access panel was screws yet the gear door hinge was the inward side, otherwise I would have simply unscrewed it. It does not look trivial to remove as mentioned by kortopates, thank you.  Any idea how difficult it is?

I’m not waiting my AP to come back, I was already uncomfortable by his low priority concern. I will have a local guy confirm cause and get overhauled unit or mine overhauled.

Thanks to all to who gave their thoughts.

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I did see that the outer side of the access panel was screws yet the gear door hinge was the inward side, otherwise I would have simply unscrewed it. It does not look trivial to remove as mentioned by kortopates, thank you.  Any idea how difficult it is?

If I can do it, anyone can. I didn’t have to remove the gear door, but did have to disconnect it to allow access to the screws, had to move the drain hoses as well. I had an additional filter that I removed and disassembled to clean which I don’t think the your pump requires. All in about an hour of work.
Caveat: I have a 78, so my experience might be different. I took care of removal, my A&P handled reinstall.
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7 hours ago, SkipSS said:

I didn’t think any fuel leaking from anywhere near the engine is common or normal, I was surprised by mechanic’s reply.  

I did see that the outer side of the access panel was screws yet the gear door hinge was the inward side, otherwise I would have simply unscrewed it. It does not look trivial to remove as mentioned by kortopates, thank you.  Any idea how difficult it is?

I’m not waiting my AP to come back, I was already uncomfortable by his low priority concern. I will have a local guy confirm cause and get overhauled unit or mine overhauled.

Thanks to all to who gave their thoughts.

If the inner row of screws are under the door hinge, you’ll need to remove the door link first.  You’ll need a few simple tools, 3/8” wrenches and sockets and Phillips and common screw drivers.  Be careful with the link, the lower end has 4 small bushings, if you tak the lower end off note their position, the upper end does not.

Remove the screws from the door hinge and the perimeter of the panel, at the front end remove the screws or bolts holding the vent hoses in place, access these by opening the cowl flaps fully, then disconnecting the cowl flap quick connector.

Once the panel is removed the pump is fully accessible.  To remove it you’ll need a few more wrench’s, 9/16”, 5/8”, 11/16” to remove the lines from the pump, turn the fuel off first.  Disconnect the power and ground wires, remove the lines, then remove the mounting clamps from the motor, usually a 11/32” or 3/8” wrench and a screw driver.

Clarence

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I had a leak a few years ago.  After pulling the access panel I found it to be a loose fuel line fitting (fore of the pump at the firewall) that needed tightened.  However, the fuel leak traveled down the fuel line and started dripping at the fuel pump originally making me think the fuel pump was leaking.  Had to buy a Crows foot to tighten.  No problems since.

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  • 2 weeks later...

Just another vote for Aeromotors. Had a burnt out fuel pump in an M20E and called Aeromotors. Due to the upcoming Christmas/New Years holidays, Teresa on the phone offered to just do an exchange instead of an overhaul for the same price. That way I wouldn't have to wait until after the holidays. Sent it out on a Tuesday and had the overhauled exchange back by Saturday. Very quick service from them, and 5 hours labor for the shop to remove and replace. 

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3 hours ago, KaiGywer said:

Just another vote for Aeromotors. Had a burnt out fuel pump in an M20E and called Aeromotors. Due to the upcoming Christmas/New Years holidays, Teresa on the phone offered to just do an exchange instead of an overhaul for the same price. That way I wouldn't have to wait until after the holidays. Sent it out on a Tuesday and had the overhauled exchange back by Saturday. Very quick service from them, and 5 hours labor for the shop to remove and replace. 

5 hours to R&R the pump? Seems like a lot.

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  • 4 weeks later...

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