Gas tank - two line plumbing plan
01-13-2013, 12:07 AM
#27
Senior Member
My Feedback: (13)
Join Date: Jul 2005
Location: Salem,
OR
Posts: 1,686
Likes: 0
Received 0 Likes
on
0 Posts
RE: Gas tank - two line plumbing plan
No need to clunk the fill/drain as you should always leave at least some fuel in the tank to prevent fuel system issues. I run 3 line systems in my planes (one's more complex as it has a primer on the carb so there's a tee in the fill/return/drain line). I store my planes nose down so I only leave a splash of fuel in them but I've had the same fuel lines in my plane for over 3 years without issue, just a standard tank with Dubro stopper...
01-13-2013, 04:23 AM
#28
Senior Member
RE: Gas tank - two line plumbing plan
ORIGINAL: av8tor1977
But what I didn't like was each time you fuel the plane, you are filling it through the wrong side of the fiilter clunk and it is possible to introduce crap straight into the line the goes to the carb.
AV8TOR
ORIGINAL: BobH
Many years ago when I worked in the chain saw industry felt filtlers were the standard. The only issue with them is that after a while they tend to harden and restrict fuel. If you are aware of that and change them befor that happens you are fine. No fibers get in the carb etc. These filters are made specifically for their intended purpose.
Walboro carbs take about 10psi or more to over come the inlet needle valve. So fueling on the two line system would only be an issue if you have a lot of fuel pressure in that line. FYI I've always used a 3 line system but I don't see big problems with either situation provided you do the right things in the first place.
Many years ago when I worked in the chain saw industry felt filtlers were the standard. The only issue with them is that after a while they tend to harden and restrict fuel. If you are aware of that and change them befor that happens you are fine. No fibers get in the carb etc. These filters are made specifically for their intended purpose.
Walboro carbs take about 10psi or more to over come the inlet needle valve. So fueling on the two line system would only be an issue if you have a lot of fuel pressure in that line. FYI I've always used a 3 line system but I don't see big problems with either situation provided you do the right things in the first place.
AV8TOR
01-13-2013, 05:16 AM
#30
Senior Member
RE: Gas tank - two line plumbing plan
ORIGINAL: BarracudaHockey
If you run a loop in your vent it wont drain gas when you tip it up
If you run a loop in your vent it wont drain gas when you tip it up
01-13-2013, 05:47 AM
#32
RE: Gas tank - two line plumbing plan
01-13-2013, 06:32 AM
#33
Senior Member
RE: Gas tank - two line plumbing plan
I do apologise for the confusion.
01-13-2013, 08:37 AM
#35
My Feedback: (64)
Join Date: Feb 2005
Location: Hot Springs Village, AR
Posts: 141
Likes: 0
Received 0 Likes
on
0 Posts
RE: Gas tank - two line plumbing plan
Interesting topic. I run both but am aware that people have issues with the 3 line setup. I notice Pe' weighed in and while I certainly respect his opinion, I never really understood WHY the 2 line arrangement causes the occasional problem. People who have had issues simply say when they switched to the 3 line system their problem was resolved. I know, "You can talk to an Engineer, you just can't get them to understand". In this case your right.
01-13-2013, 10:31 AM
#36
My Feedback: (1)
Join Date: Jun 2003
Location: Coffs Harbour NSW, AUSTRALIA
Posts: 2,306
Likes: 0
Received 1 Like
on
1 Post
RE: Gas tank - two line plumbing plan
I use both 2-line and 3-line systems, whichever suits the application at the time.
If you use a T connector, just make sure you have the correct size barb and secure it properly to eliminate any minor air leaks.
In fact, a properly fitted T is no more likely to cause a leak than the fuel dot on the third line.
Like RMH, I have a felt filter in my fuel can and toss it if the pumping slows down.
If the plumbing is done properly, you are highly unlikely to have problems with either 2-line or 3-line setups
If you use a T connector, just make sure you have the correct size barb and secure it properly to eliminate any minor air leaks.
In fact, a properly fitted T is no more likely to cause a leak than the fuel dot on the third line.
Like RMH, I have a felt filter in my fuel can and toss it if the pumping slows down.
If the plumbing is done properly, you are highly unlikely to have problems with either 2-line or 3-line setups
ORIGINAL: rmh
If there is no crap going into the tank - there is no crap going into the carb. That is my approach.
In line filters , especially he felt things, do plug up- and or restrict .
I do use a big felt filter in the fuel can and toss it if pumping slows.
If you have no problems with your setup - use it
I have no problems with mine either .
I know you have been at this for quite a while -
so have I .
There is more than one approach which works .
If there is no crap going into the tank - there is no crap going into the carb. That is my approach.
In line filters , especially he felt things, do plug up- and or restrict .
I do use a big felt filter in the fuel can and toss it if pumping slows.
If you have no problems with your setup - use it
I have no problems with mine either .
I know you have been at this for quite a while -
so have I .
There is more than one approach which works .
01-13-2013, 03:04 PM
#38
Senior Member
RE: Gas tank - two line plumbing plan
ORIGINAL: apalsson
I use both 2-line and 3-line systems, whichever suits the application at the time.
If you use a T connector, just make sure you have the correct size barb and secure it properly to eliminate any minor air leaks.
In fact, a properly fitted T is no more likely to cause a leak than the fuel dot on the third line.
I use both 2-line and 3-line systems, whichever suits the application at the time.
If you use a T connector, just make sure you have the correct size barb and secure it properly to eliminate any minor air leaks.
In fact, a properly fitted T is no more likely to cause a leak than the fuel dot on the third line.
ORIGINAL: rmh
If there is no crap going into the tank - there is no crap going into the carb.
If there is no crap going into the tank - there is no crap going into the carb.
You can't overfilter your fuel.....As they say in the army, "a penny of prevention is worth a pound of manure"
ASALWAYS...YMMV
01-13-2013, 04:01 PM
#39
Join Date: Oct 2002
Location: Lyndonville, VT
Posts: 3,305
Likes: 0
Received 0 Likes
on
0 Posts
RE: Gas tank - two line plumbing plan
As far as points of failures goes, three line wins hands down. A two line setup adds 4 extra barb/tubing connections, 3 for the Tee, and one for the fuel dot, all in the line to the carb. Three times more connections than a three line setup.
Pete
Pete
01-13-2013, 05:06 PM
#41
RE: Gas tank - two line plumbing plan
ORIGINAL: pilotpete2
As far as points of failures goes, three line wins hands down. A two line setup adds 4 extra barb/tubing connections, 3 for the Tee, and one for the fuel dot, all in the line to the carb. Three times more connections than a three line setup.
Pete
As far as points of failures goes, three line wins hands down. A two line setup adds 4 extra barb/tubing connections, 3 for the Tee, and one for the fuel dot, all in the line to the carb. Three times more connections than a three line setup.
Pete
as for failures- only one was a line coming off the clunk line inside the tank- once
01-13-2013, 05:39 PM
#42
My Feedback: (1)
Join Date: Sep 2003
Location: lebanon,
MO
Posts: 380
Likes: 0
Received 0 Likes
on
0 Posts
RE: Gas tank - two line plumbing plan
I have been re pluming my gas planes this winter and a installing small header tanks in my 3D planes as
I have gotten some air through the system when the tank is low at the worst times. It is more complicated
but I will be much less concerned with where the fuel is during crazy tricks down low. Any one else doing this?
The Jet guys always do this, I just wondered why us prop guys do not do this more.
Cheers
Tim
I have gotten some air through the system when the tank is low at the worst times. It is more complicated
but I will be much less concerned with where the fuel is during crazy tricks down low. Any one else doing this?
The Jet guys always do this, I just wondered why us prop guys do not do this more.
Cheers
Tim
01-13-2013, 05:45 PM
#43
My Feedback: (24)
Join Date: Mar 2002
Location: Bismarck, ND
Posts: 751
Likes: 0
Received 0 Likes
on
0 Posts
RE: Gas tank - two line plumbing plan
ORIGINAL: TimT2000
I have been re pluming my gas planes this winter and a installing small header tanks in my 3D planes as
I have gotten some air through the system when the tank is low at the worst times. It is more complicated
but I will be much less concerned with where the fuel is during crazy tricks down low. Any one else doing this?
The Jet guys always do this, I just wondered why us prop guys do not do this more.
Cheers
Tim
I have been re pluming my gas planes this winter and a installing small header tanks in my 3D planes as
I have gotten some air through the system when the tank is low at the worst times. It is more complicated
but I will be much less concerned with where the fuel is during crazy tricks down low. Any one else doing this?
The Jet guys always do this, I just wondered why us prop guys do not do this more.
Cheers
Tim
01-13-2013, 08:46 PM
#44
Senior Member
RE: Gas tank - two line plumbing plan
ORIGINAL: pilotpete2
As far as points of failures goes, three line wins hands down. A two line setup adds 4 extra barb/tubing connections, 3 for the Tee, and one for the fuel dot, all in the line to the carb. Three times more connections than a three line setup.
Pete
As far as points of failures goes, three line wins hands down. A two line setup adds 4 extra barb/tubing connections, 3 for the Tee, and one for the fuel dot, all in the line to the carb. Three times more connections than a three line setup.
Pete
3-line, vent has 1, fill has 4, 2 inside tank and 2 outside, and fuel supply has 4, 2 inside the tank and 2 outside; assumes no extra filters and any loops in the vent are done with fuel tubing
2 line, vent has 1, fuel supply is also the fill.....2 inside tank,6 outside the tank; also assumes no extra filters and any loops in the vent are done with fuel tubing...
How 'bout that, they are the same # points. Never wooda thunked it.......
01-13-2013, 11:18 PM
#45
Senior Member
Join Date: Apr 2010
Location: Cape Town, SOUTH AFRICA
Posts: 2,744
Likes: 0
Received 1 Like
on
1 Post
RE: Gas tank - two line plumbing plan
ORIGINAL: rmh
If there is no crap going into the tank - there is no crap going into the carb. That is my approach.
In line filters , especially he felt things, do plug up- and or restrict .
I do use a big felt filter in the fuel can and toss it if pumping slows.
If you have no problems with your setup - use it
I have no problems with mine either .
I know you have been at this for quite a while -
so have I .
There is more than one approach which works .
ORIGINAL: pe reivers
I rather have a filter in the line than crap in the carb where it can really block fuel flow.
I rather have a filter in the line than crap in the carb where it can really block fuel flow.
In line filters , especially he felt things, do plug up- and or restrict .
I do use a big felt filter in the fuel can and toss it if pumping slows.
If you have no problems with your setup - use it
I have no problems with mine either .
I know you have been at this for quite a while -
so have I .
There is more than one approach which works .
Crap can get in via the filler line. Dust, dirt on the fuel dot, dirt getting into the filler line etc these are all sources of eventual fuel filter blocking. Without at least one filter in the "to carb" line the mesh screen in the carb is going to get blocked real quickly. A filter has a much higher dirt carrying capacity than the mesh screen in the carb.
A filter in the fuel sorts out any dirt in the fuel or fuel can, it does not sort out the plane.
By your thinking, motor vehicles should nt have fuel filters on board either. Remove those filters and see how it works out for you.
01-13-2013, 11:20 PM
#46
Senior Member
Join Date: Apr 2010
Location: Cape Town, SOUTH AFRICA
Posts: 2,744
Likes: 0
Received 1 Like
on
1 Post
RE: Gas tank - two line plumbing plan
ORIGINAL: TimT2000
I have been re pluming my gas planes this winter and a installing small header tanks in my 3D planes as
I have gotten some air through the system when the tank is low at the worst times. It is more complicated
but I will be much less concerned with where the fuel is during crazy tricks down low. Any one else doing this?
The Jet guys always do this, I just wondered why us prop guys do not do this more.
Cheers
Tim
I have been re pluming my gas planes this winter and a installing small header tanks in my 3D planes as
I have gotten some air through the system when the tank is low at the worst times. It is more complicated
but I will be much less concerned with where the fuel is during crazy tricks down low. Any one else doing this?
The Jet guys always do this, I just wondered why us prop guys do not do this more.
Cheers
Tim
Because the carb has a reservoir that stores fuel before it is metered and released into the venturi airstream. This negates the need for a header tank
01-14-2013, 12:07 PM
#47
My Feedback: (1)
Join Date: Sep 2003
Location: lebanon,
MO
Posts: 380
Likes: 0
Received 0 Likes
on
0 Posts
RE: Gas tank - two line plumbing plan
ORIGINAL: TimBle
Because the carb has a reservoir that stores fuel before it is metered and released into the venturi airstream. This negates the need for a header tank
ORIGINAL: TimT2000
I have been re pluming my gas planes this winter and a installing small header tanks in my 3D planes as
I have gotten some air through the system when the tank is low at the worst times. It is more complicated
but I will be much less concerned with where the fuel is during crazy tricks down low. Any one else doing this?
The Jet guys always do this, I just wondered why us prop guys do not do this more.
Cheers
Tim
I have been re pluming my gas planes this winter and a installing small header tanks in my 3D planes as
I have gotten some air through the system when the tank is low at the worst times. It is more complicated
but I will be much less concerned with where the fuel is during crazy tricks down low. Any one else doing this?
The Jet guys always do this, I just wondered why us prop guys do not do this more.
Cheers
Tim
Because the carb has a reservoir that stores fuel before it is metered and released into the venturi airstream. This negates the need for a header tank
This true with some carbs that have float bowls, but these carbs need to run mostely up right. The walbro carbs have no reservoir and can run at any attitude. They do pass an air bubble rather quickley, but 2 or 3 seconds out of the fuel and she will stumble or quit on you. This will be my first year with header tanks so we will see how it goes.
Cheers
Tim
01-14-2013, 01:15 PM
#49
Senior Member
RE: Gas tank - two line plumbing plan
ORIGINAL: BarracudaHockey
I dont see the point of a header in a gas plane.
I dont see the point of a header in a gas plane.
01-14-2013, 03:11 PM
#50
RE: Gas tank - two line plumbing plan
ORIGINAL: TimBle
Crap can get in via the filler line. Dust, dirt on the fuel dot, dirt getting into the filler line etc these are all sources of eventual fuel filter blocking. Without at least one filter in the ''to carb'' line the mesh screen in the carb is going to get blocked real quickly. A filter has a much higher dirt carrying capacity than the mesh screen in the carb.
A filter in the fuel sorts out any dirt in the fuel or fuel can, it does not sort out the plane.
By your thinking, motor vehicles should nt have fuel filters on board either. Remove those filters and see how it works out for you.
ORIGINAL: rmh
If there is no crap going into the tank - there is no crap going into the carb. That is my approach.
In line filters , especially he felt things, do plug up- and or restrict .
I do use a big felt filter in the fuel can and toss it if pumping slows.
If you have no problems with your setup - use it
I have no problems with mine either .
I know you have been at this for quite a while -
so have I .
There is more than one approach which works .
ORIGINAL: pe reivers
I rather have a filter in the line than crap in the carb where it can really block fuel flow.
I rather have a filter in the line than crap in the carb where it can really block fuel flow.
In line filters , especially he felt things, do plug up- and or restrict .
I do use a big felt filter in the fuel can and toss it if pumping slows.
If you have no problems with your setup - use it
I have no problems with mine either .
I know you have been at this for quite a while -
so have I .
There is more than one approach which works .
Crap can get in via the filler line. Dust, dirt on the fuel dot, dirt getting into the filler line etc these are all sources of eventual fuel filter blocking. Without at least one filter in the ''to carb'' line the mesh screen in the carb is going to get blocked real quickly. A filter has a much higher dirt carrying capacity than the mesh screen in the carb.
A filter in the fuel sorts out any dirt in the fuel or fuel can, it does not sort out the plane.
By your thinking, motor vehicles should nt have fuel filters on board either. Remove those filters and see how it works out for you.
start out clean and filter at the nozzle and it all stays clean.
PS I have cars with electronic as well as cars with mechanical FI (Mercedes classics )
Filters must be used in the cars simply because the fuel you pump in is typically not finely filtered .
If your setup works for you - have at it - -
