There are some that are more sensitive than others for what ever reason. I have an old Rocket 46 that I have plugged the venture down to very small, and it will still lean out and quit when I raise the front of the test stand even when set quite rich. But my Ohlssons, Super cykes, Spitfires, and Orwicks will all have fairly broad needle settings. My Atwood Super Champion will only run well in a 2 stroke, but is still real broad on the needle setting.
The only thing I can figure is porting and the size of the venture along with compression ratio. You might want to check the size of the venture and maybe sleeve it down a little. I have to plug the venture's on my Spitfires when running fuel to be able to set the needle without it falling out. It works just fine stock on gasoline. The Orwick has the right size venture for the engine and will work well on either fuel. Most of these old engines were set up to get the most power for Free Flight planes, and need a little tinkering to make them work well in control line. I also plug the subpiston induction holes on Super Cyclones, Spitfires, and Orwicks as they run a little steadier for me. Again, your mileage may very.
Oh, one other thing. I do not know what the compression ratio is on your engine, but my Orwick is 10 to1 which is real high for a sparker. The later ones Henry lowered the compression on. I added an extra head gasket to lower it and it starts and runs much better for me with a broader needle setting, and still plenty of power to fly my 64 ounce Taurus on 67' lines. In fact, I had to go to a wood 13-6 prop to slow it down even with the timing retarded to less than half advanced. What a horse.