I tried this at "glow engines" forum without any sucess.[]
Please, any help appreciated.

"I got a Saito 100 inverted into my Tucano T27. The best I could do when adjusting fuel tank level to carb was carb center below fuel center line about 1 1/2", which is making the fuel flow by gravity and flood the engine. It's seem also to be affecting how the engine works, too rich.
I tried to find some sort of flow valve in the Rc stores here in WA, but there isn't anything like that.
What I did was building a valve by myself, using a fuel line filter. I inserted a bearing inside the filter and fixed the filter verticaly. The bearing stand by gravity over the filter inlet hole and blocks the fuel to flow by gravity. When the engine runs, the suck power of the engine moves the bearing up, opening the fuel flow as needed. It worked almost perfect, but still some improvements to make.
I'm wondering what solution you guys use when facing this issue if no changes are possible in the engine and fuel tank anymore.

thanks,

Nilo"

When I've had inverted or low-mounted engine, I usually just use a long enough bit of fuel tubing so that the tubing goes up higher than the top of the tank, then down to the engine. Then you just need to get a little air in the line when you are filling, and that will prevent the siphon. A quick prime brings the fuel to the engine to start, and the engine should start right up with no problems. Beyond that, you should be able to set the mixture of the engine more or less normally. You'll probibly have to set the idle mixture leaner than factory setting, but once set it should stay set as normal.

I've never heard or anyone using a check valve or anything like that. If it works for you, great.

Montague,

Yes, I did try what you said and it works fine before the engine stops. As soon as the engine stops, the fuel keeps running to the carb because it's lower than the tank. I could however use a stop valve to close the fuel after stoping the engine.
Would that make sence?

Nilo

I don't know about your engine, but many engines will almost totally close off the fuel line in the carb if you pull the throttle closed. Try making sure you can totally close the throttle barrel, and leave the throttle set there after the engine is stopped. That's been enough for me in the past.

Guys that run pressure tanks sometimes use a clamp on the fuel line. I've seen some hooked to the throttle servo so that the fuel line is pinched when the throttle is pulled all the way off. But that seems a bit extreme for your situation.

Easy fix. Make or purchase a hopper tank. People flying model helicopter have a similar problem with fuel tank postions. They solved this problem by placing an additional tank between the main tank and the carburator. This tank is called a hopper. Contact your local helicopter pilots and I'm sure they can be of assistance.

What about a cline fuel regulator? I have been looking at the same issue because I am going to be building a U CAN DO .46 and from what I have read it has the same problem. I haven't decided if this what I am going to do and I'm not sure if it would work in your case, its also some what expensive so at the moment I have been looking for alternatives.

There is nothing like experience!
Thanks guys, seems I have couple options now!

Nilo

I'm trying to figure out how the extra fuel tank would work on this.
How it works, please!

Nilo

That makes two of us. Fluid seeks it's own level. I'm not sure how a second tank would solve the siphon problem. I could be wrong, but I don't think that is the reason the heli guys use it. At any rate, I have a Saito 1.00 inverted in a warbird, same problem. I just clamp the feed to the carb when filling the tank and remove it at the last second before starting the engine. My engine is well broken in and tuned so it starts on the first try. If it doesn't start immediately you have to be careful not to flood the engine.