Fuel leak

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maggot

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maggot
I have a c172 o-360 a4m. When I am done flying I have fuel on the nose wheel pant and on the front of the air box. Just had carb rebuilt, did not fix it. Any suggestions ? Thx
 
Buy a Mooney with an o-360, it's supposed to leak. If a Mooney is not leaking fuel the tank is empty.:D
 
maggot said:
I have a c172 o-360 a4m. When I am done flying I have fuel on the nose wheel pant and on the front of the air box. Just had carb rebuilt, did not fix it. Any suggestions ? Thx
Click to expand...

Find the leak. Fix It.
 
maggot said:
I have a c172 o-360 a4m. When I am done flying I have fuel on the nose wheel pant and on the front of the air box. Just had carb rebuilt, did not fix it. Any suggestions ? Thx
Click to expand...

Did it leak before you had the carb work done? If not take it back to whomever did the work.
 
Check carb for a "sunk float". They might have missed it. Its a hole in the float.
Easy thing to check but some mechanics dont want to open the carb...
 
A leaking primer will also do it. But it would have to be leaking very badly, since it has to get past two check valves and the internal needle valve before it can drip out the primer nozzles and run down the manifold and out the carb.

Might be a sinking float, a misadjusted float, or a bad float needle valve.

Or even a loose fuel hose connection. Bad...
 
maggot said:
When I am done flying I have fuel on the nose wheel pant and on the front of the air box.
Click to expand...
Wait, you are flying an airplane that is leaking so much fuel that you have it dripping out of the cowl, and, you flew it after the first time you noticed?
 
maggot said:
I have a c172 o-360 a4m. When I am done flying I have fuel on the nose wheel pant and on the front of the air box. Just had carb rebuilt, did not fix it. Any suggestions ? Thx
Click to expand...

Ya gotta love FAA licensed A&P's.....:mad2::mad2::mad2::mad2:
 
James331 said:
Did it leak before you had the carb work done? If not take it back to whomever did the work.
Click to expand...

Yeah, it must be the F---ing A&P's fault he left the primer open.
 
Dan Thomas said:
A leaking primer will also do it. But it would have to be leaking very badly, since it has to get past two check valves and the internal needle valve before it can drip out the primer nozzles and run down the manifold and out the carb.

Might be a sinking float, a misadjusted float, or a bad float needle valve.

Or even a loose fuel hose connection. Bad...
Click to expand...
Now you know why fewer and fewer A&Ps will rebuild a carb or a mag. anything goes wrong it their fault.
 
coloradobluesky said:
Check carb for a "sunk float". They might have missed it. Its a hole in the float.
Easy thing to check but some mechanics dont want to open the carb...
Click to expand...

he said "Just had carb rebuilt" gotta open it to do that.
 
Noticed fuel on nose wheel pant first time, thought maybe spilled from checking sump. Cleaned it off, even more after flying it around the pattern, staying within gliding distance, a few times. Diagnosed as possible stuck float. Rebuilt carb, including replacing brass float with composit one. Three flights with no noticeable fuel leak. Flight four showed fuel on wheel pant and air box again. Been flying this plane for five years, first time for this .
 
maggot said:
Noticed fuel on nose wheel pant first time, thought maybe spilled from checking sump. Cleaned it off, even more after flying it around the pattern, staying within gliding distance, a few times. Diagnosed as possible stuck float. Rebuilt carb, including replacing brass float with composit one. Three flights with no noticeable fuel leak. Flight four showed fuel on wheel pant and air box again. Been flying this plane for five years, first time for this .
Click to expand...
If it was a stuck float, it would be leaking all the time and fuel would be running out of the carb all the time.

with the info delivered, it seems to be a primer leaking, or a leaking fuel hose.
 
Tom-D said:
Now you know why fewer and fewer A&Ps will rebuild a carb or a mag. anything goes wrong it their fault.
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Exactly.

Nor has any pilot over primed an airplane with the accelerator pump to the point it leaks on the nose wheel pant.


Sent from my iPhone using Tapatalk
 
CFI AandP said:
Exactly.

Nor has any pilot over primed an airplane with the accelerator pump to the point it leaks on the nose wheel pant.


Sent from my iPhone using Tapatalk
Click to expand...

Another issue might be priming, then waiting too long before cranking. The fuel can run down the intakes and out the carb.

But he's been flying this thing for five years. Unless he's changed his habits, there's a leak where there shouldn't be under there somewhere.
 
N801BH said:
Ya gotta love FAA licensed A&P's.....:mad2::mad2::mad2::mad2:
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Ben, we all know that you are a pretty smart engine guy but let me ask you this, have you never made a mistake? Have you never had a part fail?

Also, it might be that the rebuild was done at a 145 or at the manufacturer. If that is the case, it was most likely not done by an A&P but by a repairman. The OP did not say that it was done by his A&P. It might have been but you should not jump to a conclusion followed by ad hominem attacks against A&Ps in general.

One unfortunate aspect of a situation such as this and social media is that problems and mistakes always get brought up. The 99.99% of the time that a mechanic does his job well and everything works as advertised very seldom gets mentioned. Yet, somebody wants to be a butthead and make a comment like you did.

Ben, I enjoy the vast majority of your posts and the friendly banter you engage in with the rest of us. However when I read what I can only describe as your anti A&P vitriol, it really disappoints me.
 
Carb rebuilt by A&P. Upon further investigation, when priming, fuel is pouring out of the bottom of carb. My A&P, after talking with his colleague, said maybe float is incorrectly set. In for annual today, hope it gets worked out
 
I do not usually prime for start up. in past winters I have left the oil pan heater on continuously, therefore no priming needed. So far this winter I have not been leaving heater on, so priming is new to me.
 
I had a similar leak after I bought my plane that turned out to be a dried up fuel hose... I usually shut the fuel off when parked so it wasn't usually noticeable.
 
SkyDog58 said:
Ben, we all know that you are a pretty smart engine guy but let me ask you this, have you never made a mistake? Have you never had a part fail?

Also, it might be that the rebuild was done at a 145 or at the manufacturer. If that is the case, it was most likely not done by an A&P but by a repairman. The OP did not say that it was done by his A&P. It might have been but you should not jump to a conclusion followed by ad hominem attacks against A&Ps in general.

One unfortunate aspect of a situation such as this and social media is that problems and mistakes always get brought up. The 99.99% of the time that a mechanic does his job well and everything works as advertised very seldom gets mentioned. Yet, somebody wants to be a butthead and make a comment like you did.

Ben, I enjoy the vast majority of your posts and the friendly banter you engage in with the rest of us. However when I read what I can only describe as your anti A&P vitriol, it really disappoints me.
Click to expand...

I will try and tone it down a bit, altho.... Over the 35 years I have been flying.. I have witnessed some dumb assed., pizz poor workmanship by aircraft mechanics....

Rant off...:redface::redface:
 
Some of the Marvel Scheblers have two floats. If one has a hole in it the other float keeps it right at the brim with occasional leaks. And it tends to need an abnormal amount of leaning. Its pretty easy to check it. Just take the top off the carb, be careful dont upset anything. Leave the gas in the float bowl, take the float out and shake it and look for a hole in the seam of the brass. Get one of the new plastic float ones. They do better.
 
N801BH said:
Ya gotta love FAA licensed A&P's.....:mad2::mad2::mad2::mad2:
Click to expand...

Some A&Ps just try to match the chinsey **** the OEM used, got away with, violated edge distances, pizz poor wire routing level of quality. :lol:


I find it interesting that Garmin says there "should" be a minimum of 6 feet between com antennae, ever looked at the top of new SEP Cessna? There isn't 6 feet spacing. My old plane has ~ 3.5 foot.

GPS antennae are supposed to be >2 feet from any com antenna.
 
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There is a 1/8 inch pipe plug on the back side of a Marvel Schebler carb bowl that allows a jury rigged plug and 1/8 inch OD flex hose as a standpipe to be epoxied and screwed in. This allows the actual float level to be measured without removing or disassembling the carb. Look for a sign of the level slowly creeping up if the needle & seat is leaking.

Obviously you can't fly with this screwed into the carb.
 
maggot said:
I do not usually prime for start up. in past winters I have left the oil pan heater on continuously, therefore no priming needed. So far this winter I have not been leaving heater on, so priming is new to me.
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If fuel from priming is still on the wheel pants after going for a ride, then it's probably not from priming.
 
N801BH said:
I will try and tone it down a bit, altho.... Over the 35 years I have been flying.. I have witnessed some dumb assed., pizz poor workmanship by aircraft mechanics....

Rant off...:redface::redface:
Click to expand...

You should visit the NTSB database and compare pilot error fatal accidents to mechanic error... tell me which is the bigger group of dumb's.... I'm sure, I'm way more afraid of a pilot killing me than they should be of the contrary.
 
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GlennAB1 said:
You should visit the NTSB database and compare pilot error fatal accidents to mechanic error... tell me which is the bigger group of dumb's.... I'm sure, I'm way more afraid of a pilot killing me than they should be of the contrary.
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Yeah, BUT...

You can make a decision to NOT ride with pilots...

Pilots HAVE to use FAA licensed A&P's for maintenance....

Thing about your comment..

If the pilot screws up.. HE dies..

If the mechanic screws up.. the pilot dies...

Ya see where I am going with this..:dunno::rolleyes:
 
Pilots never have to fly in an aircraft they deem unsafe, for that matter, pilots don't have to fly at all. I have no choice when I have a roadtrip and I have to jumpseat. I could find another line of work, guess we all could.
 
I would think that fuel leaked in flight (or any time the engine is running) would not show up on the nose pant. Unless it continues to leak after shutdown.
 
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