Fuel Pump Dripping

[cferr59]

Hello,

In the ongoing saga of my gascolator problem, I put everything back together and ran the fuel pump to check for leaks.  Well, nothing I touched is leaking, but the I discovered that the fuel pump is dripping from its drain hole.  It drips about 1 drop every 4 seconds.  I imagine it has been doing this for some time and I just never noticed.

I'd rather wait until annual to get it fixed, but I also have a feeling I should just do it now. 

[carusoam]

Negative, captain...

There is no waiting on that one... 

Fuel pumps are important for flight...

That drip occurs when something is no longer working as expected with the pump.

Could be (one of the dual diaphragms has broken... mechanical pump), or it needs to be re-sealed (electric pump)...

Stuff wears out... and has a back-up... this one is now running on its back-up...

Pull and send out... it comes back like new in a few days...
 

What looks like a drip every few seconds....

have somebody sit in the cockpit, and turn the pump on... from the outside, you can see how much fuel actually gets pumped on the floor.... 

PP thoughts only, not a mechanic....

[ArtVandelay]

Pull it and send it to Aeromotors LLC.

[cbarry]

I initially thought I had the same issue as you with the gascolator.  However, it was the fuel boost pump that was dripping.  I also thought it could have a piece of contaminant between the fuel pump veins and the internal seal that might be the cause of the drip.   I ended up replacing the pump assembly and solved the issue.

[cferr59]

4 minutes ago, carusoam said:

Negative, captain...

There is no waiting on that one...

Always fun when you fix one thing and find another problem.  I guess it is going to Aeromotors on Monday.

[ShuRugal]

I bumped into an E model pilot last year at First Flight who was having a similar problem - the line fittings on the pump were not right enough, and it leaked about 8 oz per minute when the pump was running. I helped him troubleshoot it for about half an hour (mostly by watching it drip while he tried different things), and in the end he decided to call for a mechanic from one of the neighboring fields.

He probably could have gotten the plane to that field safely - it had obviously been like that in the fight in, but the short field at First Flight and the lack of anywhere to set down that wasn't either water or town made calling someone out a smart (if expensive) call.

The thing I pointed out to him that got him to decided to wait for help water than fly it out was that even though it wasn't leaking with the engine running and the boost pump off, that was not an indicator that it was safe. Part of his fuel system was open to air - either fuel is coming out, or air is going in, and engines don't run so well on air...

Your fuel pump weep hole is open to air. If fuel can get out with the pump running, then air can get in with only the engine pump sucking.

[carusoam]

58 minutes ago, cferr59 said:

Always fun when you fix one thing and find another problem.  I guess it is going to Aeromotors on Monday.

The really cool thing is when you find something before you need too... 

I had somebody wave at me to tell me my fuel pump was peeing on the ground.... just after start-up...

For the IO550s.... that electric fuel pump comes on based on throttle position...

An unknown amount of fuel is being tossed overboard... while not getting all the way to the engine...

It takes a decade to get everything fixed this way...

After a decade... you get to execute round two for a lot of things...

Best regards,

-a-

 

[cferr59]

1 hour ago, carusoam said:

The really cool thing is when you find something before you need too... 

I had somebody wave at me to tell me my fuel pump was peeing on the ground.... just after start-up...

For the IO550s.... that electric fuel pump comes on based on throttle position...

An unknown amount of fuel is being tossed overboard... while not getting all the way to the engine...

It takes a decade to get everything fixed this way...

After a decade... you get to execute round two for a lot of things...

Best regards,

-a-

 

That is true, better to find it in my hangar than at a remote airport on a trip.  I got the pump out and there is blue staining on the outside.  It is a bit easier to pull the fuel pump on a Piper, but it was still easier than creating the shipping labels to send it to Aeromotors on the UPS website...

[Guest]

6 hours ago, cferr59 said:

Always fun when you fix one thing and find another problem.  I guess it is going to Aeromotors on Monday.

That’s a good call, the seal that keeps the fuel from mixing with the electrons is worn out.

Clarence

[cferr59]

28 minutes ago, M20Doc said:

That’s a good call, the seal that keeps the fuel from mixing with the electrons is worn out.

Clarence

I suppose 55 years of service is a decent run.  Nothing in the logs that it was ever replaced.

[cliffy]

That's why doing forensic log book exams is so much fun.  You find so many interesting things from over the years.

When I bought my Mooney I went through each log book and made a date/time list of all parts that were ever changed on the airplane. So much easier to read that kind of list than sticky notes in the books. Gives a real good picture of what kind of maintenance the bird has had. 

[cferr59]

34 minutes ago, cliffy said:

That's why doing forensic log book exams is so much fun.  You find so many interesting things from over the years.

When I bought my Mooney I went through each log book and made a date/time list of all parts that were ever changed on the airplane. So much easier to read that kind of list than sticky notes in the books. Gives a real good picture of what kind of maintenance the bird has had. 

It turns out I was wrong.  The pump has a 1968 manufacture date stamped on it and the first log entry for the aircaft is in 1965.  I found an entry for replacing the pump in 1969 so it looks like the first one made it 4 years and this one made it 51.  As I was cutting the safety wire off, I was thinking how no one had touched it in at least half a century.  When I have some time, I'm going to do the same.

[PT20J]

The mechanical pump on the engine has a drain that will dribble gas if one of the diaphragms has a leak. The boost pump has a drain (shown in the OP) that will dribble gas if the internal seal has a leak. It's good to check both of these on post flight. Also, during annual it is good to check all the B nuts for security and torque seal them. I once had the B nut back off (apparently undertorqued at the factory years before) on the outlet of the engine driven fuel pump. I arrived back at the airplane after a short flight to find gas dripping on the nose wheel. 

Skip

[ArtVandelay]

7 hours ago, cferr59 said:

It turns out I was wrong.  The pump has a 1968 manufacture date stamped on it and the first log entry for the aircaft is in 1965.  I found an entry for replacing the pump in 1969 so it looks like the first one made it 4 years and this one made it 51.  As I was cutting the safety wire off, I was thinking how no one had touched it in at least half a century.  When I have some time, I'm going to do the same.

 

New owner may have run it continuously which it wasn’t designed for, so that’s why it had a short life. Supposedly the Aeromotors overhaul will make it capable of running continuously. I have forgotten to turn it off myself, since then hangar fairies added a indicator light.

[tmo]

It does say "DUTY - CONTINUOUS" in the pic in 1st post...  Granted it's the 2nd pump, the first one could have been different.

[cliffy]

The electric pump has to run continuously if the engine pump fails, until you get to the nearest suitable airport. :-)

[Jim Peace]

I was speaking to the owner of the company I bought my new pump from, CJ aviation,  at a SNF one year and he said that even though it is not a continuous certified pump that it can run for hours and hours with no damage....I dont want to find out

 

[DXB]

On 5/9/2020 at 11:30 AM, cferr59 said:

Hello,

In the ongoing saga of my gascolator problem, I put everything back together and ran the fuel pump to check for leaks.  Well, nothing I touched is leaking, but the I discovered that the fuel pump is dripping from its drain hole.  It drips about 1 drop every 4 seconds.  I imagine it has been doing this for some time and I just never noticed.

I'd rather wait until annual to get it fixed, but I also have a feeling I should just do it now. 

Chris,

Some great catches here. Makes me want to look under the same panel on my bird.  I think my pump was overhauled in late '90s . BTW Weldon makes a replacement pump that's supposedly hardier if you wanted to go new.  Then again 51 years service ain't bad.  

Also BTW what are your max fuel flows like at takeoff?   I'm still chasing my CHT issue, and it may come down to modding my carb beyond the normal fuel flow of the richer carb model. Your temps seem very manageable.

[carusoam]

Modern Mooneys locate the drain over / in a hole in the belly panel...

This allows for a brief inspection of a blue goo glob growing at the tip...

They have a tendency to fail very slowly... at first...

OH at 25years may make more sense than cutting a hole and extending the drain...

At least something to look for if you smell fuel in and around the cabin...

PP thoughts only, not a mechanic...

Best regards,

-a-

[cferr59]

25 minutes ago, DXB said:

Chris,

Some great catches here. Makes me want to look under the same panel on my bird.  I think my pump was overhauled in late '90s . BTW Weldon makes a replacement pump that's supposedly hardier if you wanted to go new.  Then again 51 years service ain't bad.  

Also BTW what are your max fuel flows like at takeoff?   I'm still chasing my CHT issue, and it may come down to modding my carb beyond the normal fuel flow of the richer carb model. Your temps seem very manageable.

I thought about that, but $450 is a lot cheaper than the Weldon pump.  Also, apparently Aeromotors has some modifications that make the pump more reliable (per another thread).  I also just bought a Surefly on sale so my budget for aircraft parts is getting low.

I just looked though a bunch of flights on Savvy and it looks like I typically running 18.5gph.  It seems to flucuate between 18-19gph, but always on the high side of 18.

 

[DXB]

28 minutes ago, cferr59 said:

I thought about that, but $450 is a lot cheaper than the Weldon pump.  Also, apparently Aeromotors has some modifications that make the pump more reliable (per another thread).  I also just bought a Surefly on sale so my budget for aircraft parts is getting low.

I just looked though a bunch of flights on Savvy and it looks like I typically running 18.5gph.  It seems to flucuate between 18-19gph, but always on the high side of 18.

 

I think that may be the key difference in climb at least.  My max is in the mid-high 17s.  1gph could make all the difference for cooling - the added power is spectacular.  I think you'll like the Surefly

[cferr59]

15 minutes ago, DXB said:

I think that may be the key difference in climb at least.  My max is in the mid-high 17s.  1gph could make all the difference for cooling - the added power is spectacular.  I think you'll like the Surefly

Certainly that could make a big difference, but I imagine the carb has to be taken apart to adjust that (not sure, but that is how it works on most carbs I have worked on).  I was planning on waiting until annual, but I might see if Jim can install it or at least supervise me installing it.  Not sure I can let it sit in the box until November.

[DXB]

20 minutes ago, cferr59 said:

Certainly that could make a big difference, but I imagine the carb has to be taken apart to adjust that (not sure, but that is how it works on most carbs I have worked on).  I was planning on waiting until annual, but I might see if Jim can install it or at least supervise me installing it.  Not sure I can let it sit in the box until November.

You're correct - need to pull the carb - pretty big job.  There's one specific shop that does the modification on the jet. I wonder if yours already has had it done. 

I think the surefly install is a half day job for folks who've done them before, more like a day for someone handy with regular mags but unfamiliar with the surefly.

[PT20J]

3 hours ago, DXB said:

I think that may be the key difference in climb at least.  My max is in the mid-high 17s.  1gph could make all the difference for cooling - the added power is spectacular.  I think you'll like the Surefly

Just for reference, the 200HP IO-360 flows betweeen 17 and 18 gph at sea level, standard day. I checked this number three ways: Test cell data from Lycoming supplied with my rebuilt engine, flow bench specs I obtained from Precision Airmotive for the specific RSA injector system used on this engine, and my own fuel flow indications (New floscan transducer, properly installed, feeding a Shadin totalizer that has been cross checked with two others).

I have a A&P friend with a C and his climb CHTs run 400+ on the JPI even after the carb mod. The previous owner was also an A&P and both of them spent a lot of hours trying to figure it out. Nothing seems to help except airspeed.

Skip

[DXB]

24 minutes ago, PT20J said:

Just for reference, the 200HP IO-360 flows betweeen 17 and 18 gph at sea level, standard day. I checked this number three ways: Test cell data from Lycoming supplied with my rebuilt engine, flow bench specs I obtained from Precision Airmotive for the specific RSA injector system used on this engine, and my own fuel flow indications (New floscan transducer, properly installed, feeding a Shadin totalizer that has been cross checked with two others).

I have a A&P friend with a C and his climb CHTs run 400+ on the JPI even after the carb mod. The previous owner was also an A&P and both of them spent a lot of hours trying to figure it out. Nothing seems to help except airspeed.

Skip

Good to know thanks! I was wondering that about the IO-360 actually.  They probably don't end up with lean cylinder as easily I imagine at that fuel flow - my issue is really just one cylinder.  Going really high on the fuel flow is a bit of a blunt instrument, but I may run out of other options for a carb'd bird.  I hate seeing a 450 CHT in climb - that stresses me out.