What is this hose for in the fuel injection system?

[shawnd]

Trying to understand what this second line from the fuel manifold for. Of course the one covered in firesleeve is the fuel line but this second one connects on the port side of the manifold, snakes underneath the port side intake manifold and connects to the firewall on the passenger side. TCM IPC shows only one connection - the fuel line. Any ideas? I am trying to see if I can get a longer hose to cleanup how its routed around through the wall behind the engine.

Engine TSIO360MB-6B

PS. been away - stories to tell, will update in  post once the plane is all fixed up.

 

 

[N201MKTurbo]

I haven't worked on any 252s, but is it your manifold pressure line?

[shawnd]

Thanks and hmm, I have no idea. I guess I am missing some other areas of knowledge around this area. For ex, when I lean my engine out during runup, once I push the throttle in, the fuel flow also increases. How does this happen when the mixture control is untouched?

If it is the manifold pressure line - is it safe to unplug it and replace it with a longer line.  Anyone have a part # or specifics what it can replaced with?

[MB65E]

Look like just a fuel pressure line for the instrument panel. 
-Matt 

[EricJ]

6 hours ago, MB65E said:

Look like just a fuel pressure line for the instrument panel. 
-Matt 

^^This.   It's the line to a wet fuel pressure gauge.   Get yerself an engine monitor and ditch that dude. 

[N231BN]

252's didn't have a fuel pressure gauge, this isn't an early 231/262 is it?

[carusoam]

The only reason a fuel line would carry fuel to the cockpit would be a mechanical FuelP gauge it is feeding...

Most get eliminated by sending signals on wires instead... 
 

PP thoughts only, not a mechanic...

Best regards,

-a-

[EricJ]

4 minutes ago, N231BN said:

252's didn't have a fuel pressure gauge, this isn't an early 231/262 is it?

If it has a fuel flow gauge it's the same thing, it uses the fuel pressure out of the flow divider to drive the gauge.

 

[shawnd]

It has the Hoskins FT-101 fuel flow gauge. It’s scary that it’s carrying fuel straight into the cabin! Yeah Aircraft is a M20K 252. No fuel pressure gauge.

[pkellercfii]

That’s the pressure sensing line for the manifold pressure gauge.

 

—Paul

 

[Guest]

19 hours ago, shawnd said:

Trying to understand what this second line from the fuel manifold for. Of course the one covered in firesleeve is the fuel line but this second one connects on the port side of the manifold, snakes underneath the port side intake manifold and connects to the firewall on the passenger side. TCM IPC shows only one connection - the fuel line. Any ideas? I am trying to see if I can get a longer hose to cleanup how its routed around through the wall behind the engine.

Engine TSIO360MB-6B

PS. been away - stories to tell, will update in  post once the plane is all fixed up.

 

Are you sure that the line goes the the fuel manifold?  The hose at the arrow at the manifold appears to have a hose clamp, if so, this the vent line.

I should have a 252 in the shop today, I’ll look at it.

Clarence

 

[carusoam]

Shawn,

Have a look at your baffle seals...

These are important devices to enable proper cooling of the CHTs...

When in good condition, they are semi-rigid, and have good smooth contact with the top of the cowl...

The ones pictured above look like they are in need of aviation’s blue pill.... 

Without a good seal, the air pressure will escape past the seal, and not get forced down through the cooling fins....
 

What else do you have going on?

PP thoughts only, not a mechanic...

Best regards,

-a-

[N231BN]

12 hours ago, EricJ said:

If it has a fuel flow gauge it's the same thing, it uses the fuel pressure out of the flow divider to drive the gauge.

 

Yes, but only the early 231's had the wet fuel flow gauge like a bonanza, they changed them all out to flow transducers.

[shawnd]

@carusoam the baffle seal looks bad in this picture but isn't that bad. Still flexible and engine gets plenty of cooling based on CHT/EGT temps on JPI. However, I do plan on replacing them with McFarlane CowlSavers.

@N231BN You are right that the 252 has a flow transducer, see pic. "Fuel flow is represented digitally and indicates volume of fuel being used in GPH".  Having said that, its not part of the manifold based on the image, but maybe the image is just supposed to give a high level idea.  Would be great to know if there is a part # for this hose. @M20Doc is it possible to replace it with a slightly longer one to route it better?

 

[N231BN]

As Paul mentioned above, that has to be your manifold pressure line. I think you may have not traced that hose correctly as the one coming off the bottom of the spider should just be a drain line.

[shawnd]

Hmm yeah could be - will do tonight. Thanks!

[Phil EF]

While you have it open, might be wise to accomplish Continental Motors CSB 19-01 to remove the diverter (primer)valve.  This removes a source of engine failure and at the same time improves ease and smoothness for starting both cold and hot.  
Phil

[shawnd]

37 minutes ago, Phil EF said:

While you have it open, might be wise to accomplish Continental Motors CSB 19-01 to remove the diverter (primer)valve.  This removes a source of engine failure and at the same time improves ease and smoothness for starting both cold and hot.  
Phil

I am planning on taking the plane down to a MSC soon for a few other things. Will have them take care of this as well. Thanks for the pointer.

[carusoam]

The POH of modern Mooneys supplies important info that you can rely on... that is their intent...

No, they aren’t perfect... and don’t get updated very well over time...

But, your FF sensor is in line with the fuel line going to your engine, then connected by wires to a display on the panel... according to the drawing above...
 

Back to finding out what hose you have, and what it is attached to...

Best regards,

-a-

[carusoam]

On 9/21/2020 at 10:30 PM, shawnd said:

It has the Hoskins FT-101 fuel flow gauge. It’s scary that it’s carrying fuel straight into the cabin! Yeah Aircraft is a M20K 252. No fuel pressure gauge.

Remove the scariness... with knowledge...

The FT101 is A digital display / counter / adder... connected by wires out to the FF sensor near the engine...

Fuel stopped getting delivered to the cockpit via instruments somewhere along the way...

Instrumentation started to improve in the 80s... better by the 90s... completely digital in the new millennium...

My 65C had a fuelP gauge that was delivering pressurized fuel... it never leaked...
 

To Add your fear back in.... the fuel tank lines run through the cabin delivering many gallons per hour not very far from your seat... they are held together by an ancient rubber hose that doesn’t get looked at very often...

Best regards,

-a-

[shawnd]

Haha - re: fuel, One of the things I had done while the cowl flap motor was out was take the belly off for a closer look and found the fuel selector valve leaking. So went ahead and had the fuel selector valve o-rings replaced. Once that was done, I wanted to replace the worn out adel clamps around the cowling and I noticed deep nicks in the ignition harness so swapped that out and, why not, replaced the spark plugs as well. Took the opportunity to get the cylinders boroscoped and compression tested.

Glad I got the opportunity to learn a ton while the plane was grounded. Best yet - looks I still have a lot more to learn!

[Guest]

On 9/21/2020 at 10:30 PM, shawnd said:

It has the Hoskins FT-101 fuel flow gauge. It’s scary that it’s carrying fuel straight into the cabin! Yeah Aircraft is a M20K 252. No fuel pressure gauge.

I’m not sure why everyone worries so much about fuel lines in the cabin.  You’re sitting between the 2 fuel tanks and the only thing that protects you from that fuel is the upholstery, as well under the floor are even more larger fuel lines.

Clarence

[ArtVandelay]

I’m not sure why everyone worries so much about fuel lines in the cabin.  You’re sitting between the 2 fuel tanks and the only thing that protects you from that fuel is the upholstery, as well under the floor are even more larger fuel lines.
Clarence

Probably the fact it’s run along with the electrical wires, having an ignition source bundled with fuel source is a bad idea.

[carusoam]

Use both eyes when you look at fuel running through the cabin...

Doc’s comments are spot on!

there is a cork seal, possibly replaced with rubber, on the other side of a piece of fabric in M20Cs...

You knew you had a fuel level sensor leak, because the fabric on the wall started turning blue... And collecting under the rug at your kids’ feet... the rug turned a nice shade of blue as well...

In modern planes, instead of fabric... it is a piece of thermoformed ABS...

If I were to change a design... an extra piece of aluminum in certain places to keep fuel further away from the passengers...

Fuel and ruptured wings is the biggest challenge we are going to face once on the ground after an off field landing...

Avoid poles and trees at all costs...   if you get a choice... take the trees on your left hand side... you only have exits on the right hand side... or you may have to make your own emergency exit...
 

PP thoughts only, not a mechanic...

Best regards,

-a-

[LANCECASPER]

On 9/22/2020 at 10:48 AM, shawnd said:

@carusoam the baffle seal looks bad in this picture but isn't that bad. Still flexible and engine gets plenty of cooling based on CHT/EGT temps on JPI. However, I do plan on replacing them with McFarlane CowlSavers.

 

The picture says it all, the baffle seals are that bad.

Way beyond flexible, they are floppy. Air being pushed across the top of the engine at 200mph will blow them back so that they let air flow over the top, instead of making the air go down over the fins in your air-cooled cylinders.

I bought an Encore with 750 hours on it where the original owner had just replaced all six cylinders and couldn't figure out why the cylinders went bad so soon even though the temps were all in the green. The baffle seals on that airplane were in almost as bad of shape as yours. The first thing I did was replace them with a baffle seal kit from @GEE-BEE