New Member, New Owner, First Flight and Fuel Starvation

[Paul - M20C]

Just purchased my 1965 M20C on Friday and had my first flight in it today (transitioning from a C172M).  We went for 20 minutes in the pattern and on the second take off the fuel pressure went to 0 in/lbs and the engine started stuttering below 400'.  She kept running and we continued to climb so we requested priority (we were currently cleared #2) and asked for the intersecting runway.  Yes, we could have declared an emergency but there was no need since the controller was already working with us and we were continuing to climb.  We made TPA so we requested the primary runway and made an uneventful landing.  My second landing in her was with a hiccuping engine and was better than my first landing.  You could say I was committed to that landing.

She shows good fuel pressure at idle but if you run her up to over 2000rpms she reads 0 fuel pressure with or without the boost pump on and starts stumbling.  I wish I'd thought to run her up on the other tank to see if there was a difference but I didn't think about that when we were testing her out after taxing back to my hangar.

When I bought her on Friday my mechanic flew her to my home field for me since I bought it at a 2300' grass strip that was a little rough (my insurance requires 5 hours transition training for passengers so I decided not to fly it at all until I've finished that training).  My mechanic had no problem with her, but he had her running on the right tank.  The left tank was the fuller tank after I had fuel added yesterday so we used the left tank today.  If we had more altitude or she had quit completely I would have switched tanks when she started stumbling, but in my mind a stumbling engine that still climbs is better than a quiet engine so I changed nothing and kept flying.  The instructor (first time flying with him) was also telling me not to change anything and giving me instructions.

Fuel strainer inspection/cleaning is considered Preventive Maintenance and allowed under Part 43 for an owner so I plan on taking a look at her tomorrow now that I've downloaded the parts catalog and the maintenance manual.  According to the service manual a 1965 M20C has the strainer on the bottom side of the fuel selector in the nose gear wheel well.  Looks like one bolt and it can be removed and inspected/cleaned according to the manual (Page 149 in the parts manual and 2-4 to 2-7 in the service manual).

I'm glad we decided to do the first hour of my transition training at my home field before going anywhere else and I'm really glad that the problem didn't pop up on my mechanic while he was flying it back in between fields.  It was only a 15 minute flight for him but putting it in a field would have been a bummer.  When we get this sorted out I plan on requesting a VCOA for the first flight so we can stay above it in case it happens again.

Am I on the right track on what probably caused this and what I should inspect first?  

[Mooneymite]

Fuel vent clogged?

Run the engine with the fuel cap removed.  See if the fuel pressure is normal.

 

 

[Paul - M20C]

20 minutes ago, Mooneymite said:

Fuel vent clogged?

Run the engine with the fuel cap removed.  See if the fuel pressure is normal.

 

 

Great advice.  Thanks.

[BigD]

I know this might be an obvious suggestion, but I’ll offer it anyways... is there water in tanks? When I first picked up mine, it had been sitting outside during a heavy rain, and there was so much water in tanks that fuel strainer was absolutely full of water. 

[carusoam]

Take it slowly there friend... 

There is nothing normal about having fuel flow slow down on you like that.  You have two fuel pumps, both are capable of doing the job... Something is getting in the way...

There is nothing normal about test flying a new to you airplane to find out what is working and not working.

Check your engine instrument data to see how hot the EGTs got during the climb with no fuel pressure...

Got engine data to go with that experience?

How Long has this plane been sitting before you bought it?

Do you feel lucky?

Did you have a pre-purchase inspection before buying this plane?

 

For background...

My first taxi in an M20C ended unceremoniously with the engine dying, because there is no both on the tank selector... there were no detents for L or R either... just a smoothly twistable handle with no way of knowing if the fuel was ever going to flow...

My experience sounds similar to yours.  

Fear of switching tanks when something is going wrong... why is that?  The procedure says a couple of things like switching tanks, turning on the fuel pump, operating the mixture control, switching magnetos... do you  have the procedures... they come in a POH that is more than a decade newer than your airframe... there is a POH in the downloads section around here...

All of these things should be able to be put back. Unless you haven’t checked to see if that is true on the ground first...

Are you signed up for transition training to cover the specific details of the M20C?  There is actually such a thing...

Reinventing the wheel can be fun.  It can also get very expensive pretty quickly.

Sorry to sound older than your Dad.  Just been there and did it the same way.... before there was an Internet...

My C sat for a while before I bought it.  It stuck a valve in its first 10 hours of flight.  The exhaust valve crashed into the piston on climb out just shy of the TPA... short on HP was real interesting return to the next runway...

 

Tell us about yourself, what you are trying to do, and how you are getting ready to proceed.

 

Doing your maintenance like checking the fuel screen, comes with experience.  The first time, you do with your mechanic because making a mistake can be...  very expensive.  The FAA publishes a list of what an owner/PP can maintain... this may be on the list, but realistically it’s not an oil filter or air filter. Things that are made to be changed by ordinary PPs....

It could be something as simple as you didn’t feel like typing a long page...

But, now you opened a can o worms...

Lets make some headway together.  Add some detail to your avatar...

I wouldn’t be in a rush to go flying with Known unknowns...unless you have a lot of fields in front and after and beside your runway...  

Tell us more...

PP thoughts only, not a CFI...

Best regards,

-a-

[Paul - M20C]

carusoam -

I appreciate you taking the time to send such a long response.  Apparently though there was a miscommunication and I'm sure it's my fault.

When I say my mechanic picked up the plane - That is after we did a thorough pre-buy inspection and he picked it up and flew it to our airport after I finalized the deal.

Also when I say I hired an instructor - That was for the transition training with an instructor that knows Mooneys, but I figured that was obvious since I said today's flight was with an instructor and while my insurance company would let me fly it with no transition training I realized that I could probably use some transition training.

Thank you for taking the time to respond, but I'm not sure what you think I'm rushing into.  

[Paul - M20C]

39 minutes ago, BigD said:

I know this might be an obvious suggestion, but I’ll offer it anyways... is there water in tanks? When I first picked up mine, it had been sitting outside during a heavy rain, and there was so much water in tanks that fuel strainer was absolutely full of water. 

No water in the tanks.  I sumped them thoroughly multiple times and they do not have bladders.

It also ran for 30 mins on that tank between runup, taxi and the first lap around the patch without changing tanks.  I'm inclined to think it's a venting problem like suggested above or that tank has clogged the screen in the tank or the fuel strainer.

We'll take a good long look at both before she goes up in the air again.  I intend to start with checking the screen in the tank and the venting.  If that doesn't work we'll pull the fuel strainer.

Thanks.

[carusoam]

Paul,

My thoughts were solely that you could be engaging in your own version of transition training from C172 to an M20C. Some people actually do this from time to time... or they get some transition and skip the Mooney specific experiences like stalls and go arounds....

Without knowing whether this plane had seen action in years...

As a younger guy I expected to land off-field...  As an older guy I put in a fair amount of extra effort to avoid all that...

Please keep sharing your experience with your M20C.  There are a bunch of us around here that have started our Mooney experience with the C...

Some of us have really taken the C to the next level.

There is a lot of info around here to bring you up to speed with all the things there are to know about Your Mooney.

To Check your tank vents, they are simple metal tubes under the wing... with the cap off, you should be able to blow air easily into the tube... a long flexible wire can snake all the way to the tank.

check to see if there are any bugs in the tube... bugs usually can’t get more than a few inches inside the tube...

If the tank shows pressure while out in the sunlight... open the tank and you hear air escape... this is a sign of a blocked tank vent.  

Another sign.... the wing skin starts to oil can. It gets sucked in and starts to crush... really tough on the fuel pump.

The blocked vent comes from my M20R experience.  I never blocked a vent with the M20C...

Got any technical in you’re background? Mechanic or engineer?

Got any pilot experience in your back ground? CFI, commercial, ATP?

It’s fun getting to know people around MS.  We have such varied backgrounds...

Best regards,

-a-

[Boilermonkey]

If you take the strainer off be sure to be careful of two things. 1) It is glass and if broken can be hard to replace. 2) it can take a few tries to get it sealed when putting it back on.

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[Guest]

Paul,

I would drain/check the sumps.

check the fuel caps for O ring condition and sealing. SB M20-229A applies to caps and O rings.

take a rubber hose and hold it over the vents under the wing and blow by mouth into the tank, you should hear air enter the tank with the cap removed.

Check the gascolator for contamination.

Drain the carburetor bowl, and check the carburetor inlet screen.

Clarence

 

[tony]

There was a service bulletin years ago for a dukes boost pump, that required the owner operator to install an inline filter between the mechanical and electrical pump.  Check if you have that.  

[Yetti]

And if you have the filter past the dukes pump see if it is clogged.  Sounds like your electric. Fuel pump blowd up

[steingar]

I doubt I would trying switch tanks at low altitude.  If I'm going to die with my genitalia in my  mouth I might as well at least have the fun of pissing off the mob.

[carusoam]

9 hours ago, Boilermonkey said:

If you take the strainer off be sure to be careful of two things. 1) It is glass and if broken can be hard to replace. 2) it can take a few tries to get it sealed when putting it back on.

Sent from my Pixel using Tapatalk
 

65C got the aluminum bowl strainer beneath the pilot area floorboards...

accessible from under the plane.  Lots of screws and sheet metal...

If a new screen, or seal is needed... Lasar.com

Best regards,

-a-