One one these offer a pumped carb while the other uses pressure from exhaust. I want to use a fuel dot and will be incorporating a "T" in the line going to the carb that has a pump. I want to make sure there is a one way valve in carb that will keep from flooding when refueling. I have heard that some have but the smaller cc do not. Let me know if possible. Thanks gphil

You can do that if you want and it will work but it's not the best . The better way to plumb the tank is to just install a third line in the tank with a small clunk so you can drain the tank and run it out to a fuel dot. I run both the 10GX and 15GX and have the tanks plumbed with a third line and after 2 years no leaks and the engines run great.

I ran across a schematic showing exactly what you talked about and though so much simpler. There isn't any way the gas could blow back through the "dot" because of the carb being a pumper, correct? I did read that the system was pressurized by the crankcase????? No "T" for me , just another leak looking for a place. Thanks guy and if you have more to offer go for it. gphil

Not really because the line to the carb would need to be blocked/kinked in order for the pressure to seek out the inlet line to force gas out of/or blow out the dot ....BUT .....there is no way the engine could run that long with a blocked/kinked line as the carb would be starved for fuel and the engine would quit.

Thanks Brian good info. My first with a gas engine. I just like to get things started off in the correct direction and hope for the best. Get it right as possible the first time. . Thanks gphil

Also , the fuel needs to be and stay clean. A filtered or sintered clunk in the fuel tank plus a good in-line filter before the carb. The fuel jug needs a filtered/screened pick-up and an inline filter as well.

I run a T in the carb line on my gasser. There is no check valve, and the system works great. I have a filter between the T for the fill line and the carb so that no unfiltered fuel gets to the carb and I also am not putting any debris into the wrong end of the filter. There is no need for a check valve. The gas will flow in the direction that's easiest, and that's to the tank. I understand the concern that some have about putting a T fitting into your main fuel line and the possible leaks that could happen, but I'd argue that a 3 line system is more failure prone that a T setup is. I can put a zip tie on each end of my T fitting and I can inspect it easily. The same can't be said for a 3rd line going through the stopper of my tank. And I can fully defuel my tank if I want to, at least as well as the engine could do it were I just to let it sit and idle until it goes dry. But since my plane is a taidragger, I'd need to run a separate clunk for a 3 line system to get back there to where the last few drops of fuel are. What's the point in that?

This site is really a excellent venue for information. Ask and you will receive . New at RC but if I need to know something or get an idea come here and get flooded with answers from all corners. Much appreciated guys and thanks to the web masters for this site. gphil

Well. one can do whatever they desire. Evolution and Horizon do not recommend using "T" fittings or filler valves ...why? ...because they can leak. If you and others have had good luck then that's fine. I and many others use the third line set-up and like it.

A three line tank is required with the 10,15 and 20 cc Evo's that require tank pressure because if a tee is used for a two line tank system, gas will leak from the carb during filling and perhaps more of an issue, is that the tank can't be be drained. If there is a new pumped carb for the 15 and 20, that eliminates the need for tank pressure, a Tee might work. The instructions with such a system should detail the answer.

I and most people that i know that fly GAS use this type of Tank Filter ... one thing it seems to do besides filter is it stays wet when the tank is low and keeps the engine fro sucking air and killing from fuel starvation with fuel still left i the tank..

http://www.jackssmallengines.com/Par...FccRMwodq3kAHg

True, there is more than one way to do this that works. Respectfully though, I'm going to disagree than the T fitting method is prone to leaks. On mine, I have a barbed 3 way fitting with the lines zip tied to it. The lines themselves will break before they will slip off of the fitting, so no leaks there. And the fill line is plugged with a fuel dot so no leaks there either. I do fuel and de-fuel through the T fitting with no difficulty whatsoever. It's a simple, robust setup with nothing to wear out or malfunction. This is on a 50cc Extra 300 so it's a pumped engine, but I've also known of guys doing it on non-pumped glow engines with the same reliable results. I haven't done that personally because I haven't had a plane since learning about the merits of the T fitting setup that needed a separate fill line, but it's been done plenty by others.

I use the felt and sintered clunks and both do a good job of eliminating bubbles. They say the sintered clunks will clog up faster but I haven't seen that ...yet. I filter the fuel in/out of the jug too so that has to help. Again ....keep it clean !

The EVO 10, 15 & 20 non pumped versions have a fuel regulating carb but that regulator is designed for very low muffler pressure. Using a TEE fill will overwhelm it and produce leakage out the carb when filling. As well, the suction pressure when de-fueling will overwhelm it and cause it to yield air when attempting to defuel and of course preventing the ability to suction gas from the tank.

Otherwise, as Jester said... a Tee fitting works very well for a gas systems having a Walbro type carb.

I don't mean to imply that a Tee system will work for the Evo pump carbs on the 15 & 20 ... I don't know the answer to that.

I at this moment forget the exact nomenclature of the Evolution engine however the one I am getting is 15cc, has a pump carb , do not know which one, manufacture, I can look after this anyway I was thinking with a pump would be like any larger engine. I can do it the old way, it is just this little plane can have a cowl and just wanted to make it easier. Good info however. gphil

The Evolution site just says ,"new pumped carburetor. " So do not know the manufacture of the carb. My plane will have a cowl so wanted the option of the fuel dot but if I can't then do it the old way. gphil

You can have a fuel dot with a three line system. The dot is connected to the down tube. The carb to the felt clunk pickup and the vent tube to the muffler tap if there is one with the pumped carb, if there is not, the vent simply gets an anti siphon loop and then is fixed in place to discharge overflow usually below the plane.

You don't want to use a T fitting with any system that uses a filter klunk. If there are any impurities in the fill line, they'll collect in the front of your filter and be released to your engine all at once