Electric Fuel Pump

[N201MKTurbo]

You are right. I have serviced that filter a zillion times, but I can't seem to picture it right now.

So here is a pic of the correct installation.

[EricJ]

Another example if anybody cares:

[DCarlton]

On 5/21/2024 at 3:11 PM, Shadrach said:

You can test power to the pump with a multimeter. The leads are likely handshake connectors wrapped in plastic or heat shrink. They appear to be zip tied to the left brake line (see red arrow).  

 

Once you have verified the pump is the problem.  Turn the fuel selector to the off position. Put a catch can under the gascolator and drain it using the pull ring on the selector in the cockpit.  When loosening the pump plumbing, you will get some some leakage, but it should only be a few ounces. Nevertheless, have a catch can ready.  

Tapping it with a hammer satisfied the test requirement.  It started running after the first tap.  Will go ahead and remove, replace or overhaul.  It was last overhauled and installed in '07.  It's due.  

[DCarlton]

Appreciate the feedback from the multiple folks that chimed in on this thread.  Got a new pump installed in the correct configuration per the SB with new fuel lines.  Went with a new Weldon pump which should out last me.  Could only find one in stock anywhere and decided to grab it.  Didn't want to deal with the two way shipping and down time associated with an overhaul.  Thanks again.  

[Ragsf15e]

2 hours ago, DCarlton said:

Appreciate the feedback from the multiple folks that chimed in on this thread.  Got a new pump installed in the correct configuration per the SB with new fuel lines.  Went with a new Weldon pump which should out last me.  Could only find one in stock anywhere and decided to grab it.  Didn't want to deal with the two way shipping and down time associated with an overhaul.  Thanks again.  

Looks nice!  Did you get rid of the filter after the pump since you got the new style that doesn’t have the plastic vanes?

[jetdriven]

On 2/9/2019 at 5:08 AM, ArtVandelay said:

For Js there is a kit to convert to Weldon: 940018-503


Tom

I I tried to buy that kit, but they won’t sell it to me. They can’t get vendor parts anymore. But I think you can figure it out.

[Shadrach]

6 hours ago, Ragsf15e said:

Looks nice!  Did you get rid of the filter after the pump since you got the new style that doesn’t have the plastic vanes?

Filter is still there. I’m running without a filter on the modded Aeromotors pump without worry.

[DCarlton]

13 minutes ago, Shadrach said:

Filter is still there. I’m running without a filter on the modded Aeromotors pump without worry.

I didn't see a downside to leaving it or any guidance suggesting taking it out so we left the filter.  Will be interesting to see if it ever picks anything up.  Still hoping to get my tanks sealed later this year.  That might release some debris.  

[Shadrach]

52 minutes ago, DCarlton said:

I didn't see a downside to leaving it or any guidance suggesting taking it out so we left the filter.  Will be interesting to see if it ever picks anything up.  Still hoping to get my tanks sealed later this year.  That might release some debris.  

I did not remove a filter, we never had one. I asked Ole (Owner of Aeromotors) about adding a filter and he said that it was highly unlikely that the new vanes or any other parts could/would depart the pump so I left it at that.

Any tank debris will most likely get caught in the fine gascolator screen.

[Utah20Gflyer]

So my electric fuel pump just took a dump on my last flight to St George Utah.  So I sent my pump in to Aeromotors, LLC.   I have the Dukes 4140-00-21A pump.  The quoted cost was for an overhaul was $550 and I paid $230 for two day shipping both ways with insurance.  Aeromotors happened to have exchange unit available so I opted to take that one which gave me a total turn around of one week.   My only real hiccup was leaving the drain fitting on the pump I sent in.  My new fitting got delivered today, so once I get that screwed into the pump it will be all ready for my A&P to come inspect the work.  Here is my new pump nestled in its new home.  

[MB65E]

Both the last two owner photos did not have the correct drain connected to the pump. I have a little AN Union extension with a little 1/4 in line exiting the pump. 
I don’t think I would want to have it plugged as in a few of the photos. 
I screen shot the correct oring for the filter, thanks for the photo of the SB drawing. 
-Matt

[47U]

9 hours ago, Utah20Gflyer said:

 Here is my new pump nestled in its new home.  

Do your mounting screws have safety wire holes?  Did you use new o-rings (MS29512-06) under the inlet/outlet jam nut fitting?s  The leather back-ups were probably ok and reused?  And… put some chafe protection on the wire that is zip tied to the brake line.  Some spiral wrap… or undo the knife connection and slide some plastic hose over the wire, then reapply the zip ties (with the tail cut off flush, of course).  

Nice job!  (Sorry, my first cup of joe this morning has me a little… jittery?). 

[Utah20Gflyer]

1 hour ago, 47U said:

Do your mounting screws have safety wire holes?  Did you use new o-rings (MS29512-06) under the inlet/outlet jam nut fitting?s  The leather back-ups were probably ok and reused?  And… put some chafe protection on the wire that is zip tied to the brake line.  Some spiral wrap… or undo the knife connection and slide some plastic hose over the wire, then reapply the zip ties (with the tail cut off flush, of course).  

Nice job!  (Sorry, my first cup of joe this morning has me a little… jittery?). 

Mounting screws do have safety wire holes although they were installed with lock washers and no safety wire when I removed the pump.  This was something I noticed and was going to ask my A&P about.  
 

Yes, new o rings and leather backing looked good.  No signs of leaks when op checked.  
 

The wire coming out of the pump had an extra sleeve over the two wires already.  Are you recommending another?   Should the brake line get some protection from the Zip ties?  
 

Thanks!  

[DCarlton]

10 hours ago, MB65E said:

Both the last two owner photos did not have the correct drain connected to the pump. I have a little AN Union extension with a little 1/4 in line exiting the pump. 
I don’t think I would want to have it plugged as in a few of the photos. 
I screen shot the correct oring for the filter, thanks for the photo of the SB drawing. 
-Matt

My mechanic and I discussed the drain fitting (and the lack of it).  Mine has been plugged for at least the last 15 years.  May add one at the next annual, but I'm inclined to leave it that way without fully understanding its purpose.  Does anyone know?  What would we be draining and under what circumstances?   I've emailed Weldon as well.  

[Ragsf15e]

11 hours ago, Utah20Gflyer said:

So my electric fuel pump just took a dump on my last flight to St George Utah.  So I sent my pump in to Aeromotors, LLC.   I have the Dukes 4140-00-21A pump.  The quoted cost was for an overhaul was $550 and I paid $230 for two day shipping both ways with insurance.  Aeromotors happened to have exchange unit available so I opted to take that one which gave me a total turn around of one week.   My only real hiccup was leaving the drain fitting on the pump I sent in.  My new fitting got delivered today, so once I get that screwed into the pump it will be all ready for my A&P to come inspect the work.  Here is my new pump nestled in its new home.  

Did it just stop working or were there other symptoms?

[47U]

2 hours ago, Utah20Gflyer said:

The wire coming out of the pump had an extra sleeve over the two wires already.  Are you recommending another?   Should the brake line get some protection from the Zip ties?

(In my opinion) the heat shrink over the wires is pretty thin and doesn’t offer much chafe protection.  An improvement may be to slip a length of vinyl tube over the brake line and reinstall the zip ties.  The vinyl tube adds chafe protection for the wire and the tube from the zip tie.

Did you replace the lock washers on the screws?  The torque on a 10/32 screw isn’t that much.  Apply some torque stripe to the screws, perhaps?  The IPC for vintage aircraft doesn’t get that detailed, but the J model IPC shows four AN501AC10-8 screws, four plain flat washers, and .032” safety wire.  It’s a bit tight to safety wire, but it can be done (and builds character).  

[Utah20Gflyer]

2 hours ago, Ragsf15e said:

Did it just stop working or were there other symptoms?

It was sounding uneven for a couple years to varying degrees but always put out consistent pressure and ran relatively smoothly. Much more recently it sounded gravely and then on the last trip it started being intermittent and running slow and was barely putting out any pressure.  It never stopped completely but it definitely had a precipitous decline over the last couple flights which made me uncomfortable with continuing to run it.  
 

After hearing the overhauled pump hum smoothly, or maybe I should say roar smoothly- not sure why these pumps are so loud??  I think I can say that if your pump is not very even and smooth sounding it’s probably got some issues. 
 

I’ve considered whether I should have swapped it sooner and I’d maybe fault myself for not changing it a month ago when the decline happened, but on the other hand a trend is difficult to spot in the beginning so I probably only flew it one time more than I should have. 

[Utah20Gflyer]

30 minutes ago, 47U said:

(In my opinion) the heat shrink over the wires is pretty thin and doesn’t offer much chafe protection.  An improvement may be to slip a length of vinyl tube over the brake line and reinstall the zip ties.  The vinyl tube adds chafe protection for the wire and the tube from the zip tie.

Did you replace the lock washers on the screws?  The torque on a 10/32 screw isn’t that much.  Apply some torque stripe to the screws, perhaps?  The IPC for vintage aircraft doesn’t get that detailed, but the J model IPC shows four AN501AC10-8 screws, four plain flat washers, and .032” safety wire.  It’s a bit tight to safety wire, but it can be done (and builds character).  

I think I will add some vinyl tubing over the brake line as you suggest.  
 

I believe you about the character building nature of safety wiring a Mooney fuel pump.  If the A&P isn’t ok with the lock washers I’m in for a fun time.  

[EricJ]

5 hours ago, DCarlton said:

My mechanic and I discussed the drain fitting (and the lack of it).  Mine has been plugged for at least the last 15 years.  May add one at the next annual, but I'm inclined to leave it that way without fully understanding its purpose.  Does anyone know?  What would we be draining and under what circumstances?   I've emailed Weldon as well.  

My understanding is that the general idea is the drain feeds from the other side of a seal that is related to a common failure mode.    When the seal fails the pump starts leaking from that drain, so it is an early indication that a failure is in progress.

The mechanical pump has a similar feature with a drain between the two pump diaphragms, so if either diaphragm starts to leak, either oil or fuel will start going out that drain. 

So both of those drains are just for monitoring, e.g., during pre-flight, to see if anything is leaking out of them.

It could be that the improvements that have been done over the years, e.g., whatever it was that they did to make the pump continuous duty rather than intermittent, makes the drain superfluous or something.    I don't know, but it might be worth researching.   Aeromotors or whoever last overhauled the pump ought to know.

[Utah20Gflyer]

25 minutes ago, EricJ said:

My understanding is that the general idea is the drain feeds from the other side of a seal that is related to a common failure mode.    When the seal fails the pump starts leaking from that drain, so it is an early indication that a failure is in progress.

The mechanical pump has a similar feature with a drain between the two pump diaphragms, so if either diaphragm starts to leak, either oil or fuel will start going out that drain. 

So both of those drains are just for monitoring, e.g., during pre-flight, to see if anything is leaking out of them.

It could be that the improvements that have been done over the years, e.g., whatever it was that they did to make the pump continuous duty rather than intermittent, makes the drain superfluous or something.    I don't know, but it might be worth researching.   Aeromotors or whoever last overhauled the pump ought to know.

The overhauled exchange unit I got from Aeromotors came with one hole plugged and the other open.  I installed the plug on the top and a drain fitting on the bottom.  
 

I don’t know this for sure but I’m thinking the drain is to keep avgas from building up in the motor side of the pump in the case of a seal failure.  Seems likely if the motor filled up completely with avgas it might stop functioning?  So by allowing it to drain out it maintains functionality until it’s caught and replaced?  Just a guess but I think it’s plausible.  

[Shadrach]

8 hours ago, Utah20Gflyer said:

Mounting screws do have safety wire holes although they were installed with lock washers and no safety wire when I removed the pump.  This was something I noticed and was going to ask my A&P about.  
 

Yes, new o rings and leather backing looked good.  No signs of leaks when op checked.  
 

The wire coming out of the pump had an extra sleeve over the two wires already.  Are you recommending another?   Should the brake line get some protection from the Zip ties?  
 

Thanks!  

Factory install was with safety wire.  I would put a layer of friction tape between the zip ties and the brake line.

[DCarlton]

3 hours ago, EricJ said:

My understanding is that the general idea is the drain feeds from the other side of a seal that is related to a common failure mode.    When the seal fails the pump starts leaking from that drain, so it is an early indication that a failure is in progress.

The mechanical pump has a similar feature with a drain between the two pump diaphragms, so if either diaphragm starts to leak, either oil or fuel will start going out that drain. 

So both of those drains are just for monitoring, e.g., during pre-flight, to see if anything is leaking out of them.

It could be that the improvements that have been done over the years, e.g., whatever it was that they did to make the pump continuous duty rather than intermittent, makes the drain superfluous or something.    I don't know, but it might be worth researching.   Aeromotors or whoever last overhauled the pump ought to know.

Thanks for the discussion.  I emailed Weldon tech support.  If the drain is there to indicate seal failure, I guess the next question would be how much fuel will drain / leak, if the seal fails.  Hopefully this is no longer a common failure mode.  

[Shadrach]

23 minutes ago, DCarlton said:

Thanks for the discussion.  I emailed Weldon tech support.  If the drain is there to indicate seal failure, I guess the next question would be how much fuel will drain / leak, if the seal fails.  Hopefully this is no longer a common failure mode.  

It typically starts as a drip.