Thanks Bill,
My Kitfox Mod IV was built in 99 without a fuel return line. It had been sitting since completed testing about ten years. An A&P mechanic then bought it and cleaned it up. He had the Carburetors rebuilt by a repair facility and I bought the plane at 56 hours total time.
I flew it for 250 hours the first 9 months I had it and a certified A&P did all the maintenance.
At 250 hours the engine quit during takeoff and it all pointed to fuel system problems. I landed safely and replaced the entire fuel system. (MINUS WING TANKS) Part of the new install eliminated the gascolator but added a new header tank and three new fuel filters.
The plane has been venting fuel ever since, and I havn't flown it for anything except maintenance testing, and its annual. I replaced two bad fuel pumps for excessive pressure, and finaly reinstalled the original pump I had been flying when I had the engine failure. Funny, I'm still venting fuel from the fuel vents at low idle. This leads me to believe it is my Carbs. I tried balanceing them with the new carb mate, and even at perfect balance, they vent at low rpm. anything below 2000 starts a vibration that overflows the carbs. I QUIT.
I pulled the carbs and sent them to a repair facility to see if they are actually adustable within limits and are they actually jetted for an 80 horsepower engine. Is the idle jet different on a 80 horse vs a 100 horse? could that be the deal? I'll install the return line. It seems like it is attacking the symptom not the problem but if it stops venting fuel and helps prevent vapor lock, well, I'll fly it. Right now, I won't taxi it.
