Dunn

Dunn

I'm New Here
I have two in-line glass fuel filters between the tanks and fuel selector valve. Is it normal to have air trapped in them? After removing them for cleaning the fuel is only half way up the filter with the engine running and fuel pump on. Is there a way to bleed them?
 
Wow, 157 people have viewed my question and no responses. Did I ask a stupid question? Just trying to figure out how to get rid of the air.
 
Dunn said:
Wow, 157 people have viewed my question and no responses. Did I ask a stupid question? Just trying to figure out how to get rid of the air.
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It's certainly a reasonable question. I have two filters, but can't see through them. That's the reason I didn't respond.

L.Adamson
 
I have Earls filters...

On each tank also. They are right in front of the spar on each side between tank and valve. Have no idea whether air is trapped in them. Never has been a problem. If it makes you feel better, fly airplane knife edge and climbing for one minute each way. Should purge air from the line. Of course you'll never know because if you open the filter to see, you'll just get more air. Seriously, I have a dune buggy with the same set up with glass see through. It never gets all the air out, never runs out of gas. Good luck.
 
I didn't answer because I do not condone using glass automotive filters in airplanes for the simple reason, what happens if the glass breaks?

Get a "real" filter then you won't have to worry about either issue :D
 
Dunn said:
Just trying to figure out how to get rid of the air.
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The best way to get rid of the air is to remove the filters.
They cause two problems.
1) Crack causing fuel leak...
2) Plug up causing engine stoppage.

Check the NTSB reports...
 
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gasman said:
If you don't place the filter in line, then where do you place them? Most every car in the world has an in line fuel filter.
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You didn't say if you have fuel injection or a carb.

If you have a carb, the gascolator is typically mounted on the firewall.

If fuel injected, an inline filter is typically mounted in line with the fuel line after the valve.

I say ?typically? because some builders do different things. It is my understanding that your setup is the typical requirement in the UK.
 
I have a carb & gascolator, but installed two aluminum anodized Earls filters, when I put a fuel totalizer "turbine" in the system upstream of the gascolator. They have been no problem.

L.Adamson
 
I would think that if the filters were installed with the inlet at the bottom, outlet on top, the air would be quickly flushed out. That may not be possible with your particular install. I too would try to avoid the use of automotive inline filters.

Which RV?

Bevan
andair gascolator in each wing root. Not flying yet.
 
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Bevan said:
I too would try to avoid the use of automotive inline filters.
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I suppose I can ask why? I have them, two friends that I fly a lot with, have them. Mine are the aluminum type, and certainly as robust as fuel lines.

L.Adamson
 
Surface area

I have read on this forum in the past about people having trouble with them. Something about the paper element swelling possibly due to water if I recall. Whatever the reason, I would want to be able to easily check them for water/debris and general condition regularly (more often than annually). If they are located in the cockpit, this is difficult and messy. For what it's worth, I think I've solved this by installing Andair gascolators in the wing roots. They provide filtering and water collection just outside the tank. They are easily sumped before flight, and any crud is stopped before getting to any fuel system components. Also, in the unlikely event that there's so much crud that a filter is somewhat "restricted", I can always switch to the other tank which has it's own filter. Just my personal preference. I think the first tankfull of fuel is likely to wash the most debris into the fuel system. Bevan
 
Bevan said:
I have read on this forum in the past about people having trouble with them. Something about the paper element swelling possibly due to water if I recall. Whatever the reason, I would want to be able to easily check them for water/debris and general condition regularly (more often than annually). If they are located in the cockpit, this is difficult and messy. For what it's worth, I think I've solved this by installing Andair gascolators in the wing roots. They provide filtering and water collection just outside the tank. They are easily sumped before flight, and any crud is stopped before getting to any fuel system components. Also, in the unlikely event that there's so much crud that a filter is somewhat "restricted", I can always switch to the other tank which has it's own filter. Just my personal preference. I think the first tankfull of fuel is likely to wash the most debris into the fuel system. Bevan
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I could see problems with paper elements. The Earls filters I use, do not use paper, or any material that would seperate. There is also a lot of surface area, to filter out crud. As it stands so far, these filters have been clean for the two years I've used them. It also appears that my gascolator removed any debris during the first year (before the inlines were installed).
 
Glass Filter

I have a glass filter also and only inspect it on preflight. It has air in it during preflight, don't know when flying. Been flying for 5 years with no problem.

I put it in because of a sloshed tank and and never caught any sloosh. Lots of other crud though!
 
Thanks for all the posts! I have a carb. When I got the plane there was very little air showing in the filters, when the fuel pump was turn on it was gone. After I removed them for cleaning they now at times have 1/3 air trapped in them but the engine runs fine.
I'll try some steep climbing turns to see if that will purge it out.
What is the brand name of the better filters?
 
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