Hi,

I have a question about engine location referring to fuel thank,
As far as I know, engine needs to be in the same level of fuel thank or above,

This rule also right in case I using engine with pump such as O.S. 81FS-a Ringed w/Pump ?
[link]http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXXWH1&P=0[/link]

I would like to put the fuel thank above the engine level and I'm not sure if the engine will work
well even if I have pump plug-in.

Thanks,
Ofir

If you have a pump, it's not nearly as critical.

You can even move the tank back to put it over the CG if to care to do so.

That engine will work just fine with the tank slightly above the engine. It would likely work without the pump too.

I'm talking about 2" space
The fuel tank will be higher from the engine in 2" ?

B.T.W - I was test this scenario with glow fuel 2-stroke engine with no pump and it seems that
Engine not work very well. Only when I moved back the fuel tank to same level with engine, it was
Work well.

I have gotten away with it more then once. On a pumper the fuel goes from the tank to the regulator then to the carb, the regulator usually will stop the flow so the carb only gets what is needed. This may not always be true, that's why I say I have gotten away with it in the past. You should go to the OS factory support and ask Bill Baxter, he can give you a lot better answer more in line with the facts. I use pumpers so I don't have to worry about the tank location but I usually mount them low and over the CG, that can be quite a ways away from the engine so A pumper is a good choice for me. Bill really knows his stuff and his stuff is OS!!

If the tank is high relative to the engine you may have to use a clip on the fuel line to prevent the engine from flooding between flight when the engine is stopped. I do that when needed. A small spring clip works.

I was ask OS factory support and this what they wrote me:

"The ideal location for the tank is level or below the carb. If there is not room to lower it, the pump will help with fuel supply, and will help keep the fuel supply steady. It should run fine."
So, now its more difficult to decide, I guess I really need someone who try this one.
Maybe I try again OS support but this time ask directly Bill Baxter.

Thanks for all.