I've got the same issue as the original poster. Slow drip about every ten seconds from the fuel pump outlet.
I put a bucket under it and there's probably a gallon of gas after sitting for three weeks.

Hypothetical: if I was to put a stopper in the end of the tube, what could go wrong?

<edit>
Thought I had one. Just checked… already sold. Looks like Aeromotors is $550 for overhaul now.

Personally, I run mine for takeoff and landing.

2 reasons:
A) It keeps me in the habit for the rare times I fly a low wing airplane or other that requires it.
B) Years ago, Jeremy recommended doing so just to exercise the pump now and then. Keeps the seals moist, cleans the brushes and runs the bearings.

Seems to have worked. New price on those is about $1200.

Kirk

I'll check with Aeromotors this week.

Still looking for a reason to not just plug the outlet tube.

1) If the problem is the shaft seal like the original post, fuel could migrate to the electric motor.
2) The leaking fuel has to go somewhere…
3) Flying with a known fuel leak forward of the firewall. I think is in the bad thing category.
4) Leaks never get better, only get worse.
5) We are always free to make choices

Kirk

Same story. One day, there was a blue stain under the fuel pump. Leaking vent pipe.
Aeromotors is the best deal. Fixed price for a rebuild with better parts. Good quick turnaround. I recommend them.

Turning the fuel valve in the plane to "off" should stop the drip?

3 or 4 years ago mine had a drip every now and then. I flipped the switch on one day while we were in the middle of an annual. It ended up shooting fuel out the vent line and onto my IA's shoes.... Needless to say, it got rebuilt.... might want to check and make sure yours does not do the same thing.

Get it Rebuilt. The drip will turn to a stream. If you plug the hole, you risk fuel in places it doesn't belong. I've gone down this road last year during a trip to Oshkosh. I ended up leaking a few gallons each leg until I found where it was going. There is no way to farmer fix this. Aeromotors rebuilds are not like a napa reman. They have redesigned the bearing cap and other parts to prevent it from happening again. Just make sure you give them the correct dash- number. Don't just look at your pump, but look at the maule parts list. Some of them get replaced with the wrong stuff over the years.

If you look at this picture, how much do I need to unscrew and take off?
The green circle of the actual pump? I'd have to cut the wires up top. (probably this one I'm guessing.)
Or the blue circle which means I'd have to take the bigger (fuel?) lines out? (hopefully not this one.)

Regardless, as soon as I pull the pump, am I going to end up with gas running out uncontrolled?

What engine do you have? On the 210c, just pull the shutoff valve. I'd suspect on the other models, just turn the fuel selector to off. It'll drip for a bit, but it'll stop.

The 2 fuel lines on the bottom need to be disconnected. There are probably 4 screws on the bottom of the mounting plate that are safety wired. Remove those and the pump is free. The electrical wires probably have quick connect ends that are covered by some shrink tubing or similar. I doubt it's wired all the way into the cabin without a way to disconnect. Remove the drain tube when you send your core.

Stinger wrote: ↑

Mon Feb 26, 2024 5:58 pm

If you look at this picture, how much do I need to unscrew and take off?
The green circle of the actual pump? I'd have to cut the wires up top. (probably this one I'm guessing.)
Or the blue circle which means I'd have to take the bigger (fuel?) lines out? (hopefully not this one.)

Regardless, as soon as I pull the pump, am I going to end up with gas running out uncontrolled?

Respectfully, the questions you are asking indicate that you should not be doing this without the close guidance/assistance of your A&P. Aside from it not actually being legal for you to do this your own, it’s just not the kind of work you want to risk getting wrong.

Andy brings up a good point. It is high consequence, so if you aren't really sure what you're doing you should probably get help with it.

That being said, ever since 2009, I would argue that this would not raise any flags as being done by a pilot owner as preventative maintenance, and signed off as much.

I believe with the coleal letter of interpretation, this is a legal task without an a&p, but you should be very cautious about your comfort level.

Flame on

yanknbank wrote: ↑

Mon Feb 26, 2024 9:05 pm

Andy brings up a good point. It is high consequence, so if you aren't really sure what you're doing you should probably get help with it.

That being said, ever since 2009, I would argue that this would not raise any flags as being done by a pilot owner as preventative maintenance, and signed off as much.

I believe with the coleal letter of interpretation, this is a legal task without an a&p, but you should be very cautious about your comfort level.

Flame on

What part of the coleal interpretation makes you feel this way?

I'll post a few excerpts below. In short, the faa concludes that the list on appendix a of cfr 43 should be considered as examples of preventative maintenance, not an exhaustive list, despite how the reg and ac reads. I would consider the Dukes pump to be a simple replacement not requiring complex operations, and changing hoses is already an example on the list, as is troubleshooting landing light wiring (which would be similar so swapping the wires on the pump). It's a contentious position I'll admit. The faa has made a number of bizarre publications contradicting decades of precident, but in this case they have yet to counter their opinion. The decision is only a couple pages long. I welcome all opinions.




preventive maintenance is defined to mean "simple or minor preservation operations and the replacement of small standard parts not involving complex assembly operations."

Preventive maintenance, in general, includes tasks that are less complex than those deemed to be maintenance, and requires less sophistication in terms of the knowledge, skill, and tools required.

Many preventive maintenance tasks are listed in 14 C.F.R. part 43, appendix A, paragraph ( c ). The paragraph sets forth in 32 numbered subparagraphs items the FAA has determined to be preventive maintenance. Even though the introductory text of subparagraph ( c) states that "[p ]reventive maintenance is limited to the following work ... . " (emphasis added), in view of the broader definition of preventive maintenance in section l. l, we believe that such limitation 'is not controlling. Similarly, for the same reason, we also believe that the following sentence in Advisory Circular 43-l2A, Preventive Maintenance (which was referenced in Mr. Hernandez's letter), is overly restrictive. That sentence, found in Paragraph 3(b)(l), states: "If a task or maintenance function does not appear in the list, it is not preventive maintenance." As with the other paragraphs of Appendix A (i.e., on major repairs and major alterations), the lists are better viewed as examples of the tasks in each category-they cannot be considered allinclusive. There are, no doubt, many "simple or minor preservation operations [tasks]" and many "replacement[ s] of small standard parts not involving complex assembly operations" performed daily, especially on small general aviation aircraft, that the agency would consider to be preventive maintenance, though they are not included in the 32 listed items.

Andy Young wrote: ↑

Mon Feb 26, 2024 8:30 pm

Stinger wrote: ↑

Mon Feb 26, 2024 5:58 pm

If you look at this picture, how much do I need to unscrew and take off?
The green circle of the actual pump? I'd have to cut the wires up top. (probably this one I'm guessing.)
Or the blue circle which means I'd have to take the bigger (fuel?) lines out? (hopefully not this one.)

Regardless, as soon as I pull the pump, am I going to end up with gas running out uncontrolled?

Respectfully, the questions you are asking indicate that you should not be doing this without the close guidance/assistance of your A&P. Aside from it not actually being legal for you to do this your own, it’s just not the kind of work you want to risk getting wrong.

Questions really just so I understand what's going to happen. A&P in the hangar next door, so I can't screw up too badly.