Hello

I am setting up a BH 120 Coarsair with a Saito FA200R3. This is my VP30 fuel pump that worked great on a Saito .82/1.20 single and a OS 1.60 single. The pump runs off of the crank case presure. I have a multi cyl glow driver that is powered by a 5000 mAh NiMH 4.8 volt pack. The propeller is a 3 blade 16-8.

OK that's the set up. My question is when setting the high RPM needle valve it reached peak rpm (7500rpm) at about 5 turns out from all the way in. The rpm does not change when I open it further all the way until it comes out; when it stalls.

Since this is my first radial I am not sure if I have an issue or not. It seams to me that if I open the high speed needle valve past max rpm the rmp should drop due to a too rich mixture. Since it is not doing that I am wondering if the engine is fuel (volume) limited.

What do you think? One idea I came up with to test is to bypass the fuel pump and use exhaust pressure to drive the fuel. I have not tested this yet and was wondering if anyone has seen this befor.