sea157

My Feedback: (30)

Guys
Could someone show me a picture of a proper fuel setup?

This is mine but at full throttle I am seeing A LOT of air come up the fuel line.
I have a two line setup with a MADISON Miracle Fueler , all connections are zip tied, but I DO NOT have barbs soldered onto the tank lines, could this be my problem?
Does a carb pull that much pressure that it may be getting air in the lines even with zip ties on all connections?

This is on a DLE-30 if that means anything

STUKA BARRY

Check your fuel lines for pin holes and check your tank for pressurization, there should be no leaks.

sea157

My Feedback: (30)

I did all that but I did find some of my problem.

The fuel was foaming from vibration from lack of proper padding around the tank.
Once I padded the tank better most of the bubbles stopped until the tank gets almost empty.

Does that make any sense?

w8ye

My Feedback: (16)

Take the Madison out of the circuit and see if you still have air bubbles?

av8tor1977

My Feedback: (6)

Yes, take out the fuel filler and use fuel barbs on all the fittings. Wiring the connections is better than zip ties, because sometimes zip ties can bunch up the tubing in one spot and cause a leak, especially if you use a zip tie that is a bit too large. Wrap the wire around the tubing twice before twisting it tight. Any air leak at all is unacceptable.

Also, using a felt type fuel tank clunk like used on lawn equipment can help with keeping bubbles out of the fuel lines, as well as help empty the tank. I also like the fact that they are heavy and do their job as a "clunk" well.

Edit: I often use brass 1/8" compression tubing ferrules from the hardware store instead of fuel barbs. Much cheaper and they work great.

AV8TOR

The Ghost

I use these in all my gas setups. The only way to stop the air bubbles

Cheers

sea157

My Feedback: (30)

Thanks guys I will try the brass 1/8" compression tubing ferrules and stainless steel wire plus the felt clunks.
With these and the foam padding I added around the tank I should be good to go.

Thanks again

pilotpete2

+1 on the felt clunk, BUT, when using a felt clunk do not use a 2 line setup, in fact a 2 line setup with a gas engine is just asking for air to get into the line from the tank to the carb. A three line setup with felt clunk reduces the number of points for air to enter the line to the irreducible number of 2 points.
Pete

av8tor1977

My Feedback: (6)

+1

I never really had very many problems when I used a two line system, but I have since changed to the 3 line system and highly recommend it.

AV8TOR

w8ye

My Feedback: (16)

I've run the small Walbro felt filter inside a tank on the bench and watch for air bubbles in the fuel line while the tank gets low on fuel.

There will be no bubbles in the fuel line until the tank is completely empty. At this point the engine quits!

Apparently surface tension of the fuel versus capillary action of the felt combines to eliminate air bubbles in the fuel line?

Mntflyby

If you are using a tank with a stopper with brass or alum tubes, check the tubes for hairline cracks. Some suppliers are using thin wall tubing and just the stopper washers clamping around the tubes can cause them to crack. I went thru this with a Hangar 9 tank.

av8tor1977

My Feedback: (6)

Man, those "bean counters" will cheapen a product until it's junk won't they? I'm old enough to remember when manufacturers and dealers took pride in their products and made them the best they could; not the cheapest.

AV8TOR

MTK

Two line set-ups with the Walbro klunk works greeat. Is all I use. I suspect the OP's connections are somewhat less than perfect. barbs on all fittings practically eliminate the bubbles in the lines. If one has to use a straight fitting without barbs, a piece of fuel line should be used as a doubler onto the fittings to assure closure

w8ye

My Feedback: (16)

The major part of my younger life I worked for a prominent manufacturing company that was very cost driven. They would keep cheapening a product line to absolute failure and then go back in and spend millions to revitalize the product's worthiness.

av8tor1977

My Feedback: (6)

There's that. And don't even get me started on how the "safety" powers that be, liability concerns, and the EPA have ruined the utility and availability of the products we can buy.

I went in to buy a tube of the famous and highly regarded Yamabond a while back. I was told the original formula was banned by the EPA and they had a substitute but it doesn't work nearly as well. I wasn't even surprised....

Oh well....

AV8TOR

w8ye

My Feedback: (16)

I was disappointed that they done away with Yamabond #4 or Threebond 1194 and now have the 1184 in its place.

I bought Stihl Dirko instead. I don't like it as well as 1194 - the main reason is that Dirko is red instead of off white like 1194 - but I can get along with it.

pilotpete2

The only issue with the two line setup and felt filter clunk is that when you fill the tank, any crud that's pumped into the tank is then trapped on the wrong side of the filter, where it then can be drawn to the carb.
Pete

av8tor1977

My Feedback: (6)

That's true, plus with the fill line "T" in the supply line, there are more connections and possible leak points. Also, when you open the fuel fill, the fuel drains back into the tank which can sometimes cause re-start problems with having to get fuel back to the carb for a start, causing more starting flips and possibly necessitating choking.

AV8TOR

MTK

The number of connections between a 2-line and a 3-line is exactly the same. I counted them several years back point being that ANY connection can leak

Getting crud in the klunk isn't a problem if you filter your gas supply. I use a regular coffee filter on my funnel when I transfer from the big can to the field can. Plus I use filters on the pump. I learned a loooong time ago that's the way to assure the gas or glow fuel getting in the tank is clean. I have yet to dirty one up, neither gas nor glow.

av8tor1977

My Feedback: (6)

I don't understand. Where we are concerned about possible air leaks is only between the tank and the carb. An air leak there could easily prevent the fuel pump from pumping, or at least allow air bubbles to enter and mess with carburetion. With a 2 line system, there are connections at 1. the tank, 2., 3., & 4., at the fuel line "T", and 5., at the carburetor. Any of these leaking could cause the above mentioned problems.

With a 3 line system, there are connections at 1. the tank, and 2. the carb. They are never opened nor disturbed either. If the 3rd, dedicated fuel fill line had a small air leak somewhere, it would not affect engine operation.

I too filter my fuel multiple times, but still prefer the 3 line system for the advantages listed.

AV8TOR

captinjohn

+1

MTK

Neither do I. Why would a "connection develop a leak"? If any connection develops a leak, the tank or the carb are just as prone to develop it as as any other connection. I don't see advantages or disadvantages. Make good connections and you're good to go. Either set-up works fine and I sell both solutions. So to each his own, eh?

But I keep forgetting that people still use the yellow tubing. If one used the gas line I supply, we wouldn't be having this discussion. The polyurethane tubing is supple and flexible, day 1 to day 2000 and beyond.

mrrandyman

My Feedback: (3)

Here is how I did an Evolution 10cc engine. Yours will be different as you do not use muffler pressure I assume but the properties are the same.
Two lines are not connected in the picture but one is for the muffler and one for fueling.
In your case the line going to the muffler would be your vent line. I am using Viton tubing.
When I fuel the plane I keep an eye on the tank rather than having an overflow but it's easy in my case.

pilotpete2

Do yourself a favor and forget about the Viton on the muffler pressure/vent line. While you can't use silicone on the clunk and line to the carb with gas, you can use good old silicone on the vent line. I have an EVO 15cc, and ran silicone on the muffler pressure line for a full season without any degradation of the tubing. The momentary exposure to gas when you fill the tank doesn't seem to bother it. I tried the Viton and had too many problems with losing muffler pressure when Viton split on the pressure tap.
Pete