Hi all,

I am new to this forum and thought I would seek your guidance.

I have an Evolution .40 that has registered more than 30 flights in my trainer. I have an Evolution .46 with about the same number of flights in my Sport .40. When new, both started right up the first time and have operated flawlessly since. Both were mounted right side up.

I recently removed the .40 and mounted it in my new Seagull PC-9 ARF. The PC-9 calls for the engine to be mounted inverted. I have had nothing but problems with the engine since mounting it on the plane inverted.

The engine was tuned right side up on a test stand before mounting it on the plane. When installed (on the plane) inverted, fuel dripped steadily from the carburetor and the engine would not start. The engine had to be completely re-tuned before it would start (engine was still not running right - would stop after 30 or so seconds of operation). The fuel used in the .40 is the same fuel that I use in my .46 which fly’s great.

The fuel tank was mounted much higher than the high-speed needle valve, so it was repositioned. It is now, as close to needle valve center as the plane frame will allow. The plane is fueled with a Du-Bro Kwick-Fill Fueling Valve, mounted on the top of the topside of the plane, in front of the canopy.

Yesterday, finally after many minutes of adjustment, I got the engine (still inverted) to idle at 2800 rpm and lean out at 13,500rpm, then richened it a bit. The engine ran for about 5 minutes, throttle being moved from idle to full throttle with no hesitation. I then quit tinkering since the engine seemed to be running great once again.

Today, I tried to start the engine and it immediately hydro-locked. Fuel was once again, slowly dripping from the carburetor. I removed the glow plug, and blew out the excess fuel (engine was now right side up) and made sure the engine would turn over by hand. I then turned the plane right side up (engine inverted) and tried to start the engine again. It immediately hydro-locked. This sequence was repeated twice setting on my workbench. Very frustrating.

The only advice that I received (other than repositioning the fuel tank) from flyer's at my field is to give up with the inverted engine. Mount it right side up and fly away. Can someone give me additional guidance?