Bill: This is a classic problem with a non-pressurized fuel delivery system! When the mechanic closed the fuel valve at the bottom of the header tank in order to work on the carburetor, he allowed the fuel line from the tank through the gascolator to the carburetor to drain of fuel. when the system was reassembled fuel was more than likely allowed to seek it's own level, and the fuel delivery line was not purged of air pockets. Observe the fuel line and see if any part of the fuel line from the bottom of the header tank to the carburetor input has a small dip in it, if so, disconnect the fuel line at the input to the gascolator and push it downward allowing the fuel to flow into a container, purging the line, then quickly place your thumb over the line and reattach it to the input of the gascolator.
Air in the lines traps in the bottom of the "U" and will allow enough fuel for starting and runups to pass through but will not allow the line to fill with fuel at the moment of high fuel demand, and will stall the engine. This is a more serious problem with the ALON fuel system than with the Ercoupe fuel system. Alon made many modifications to fuel systems that were published as Service Bulletins, that were unnecessary before the true culprit was discovered. Wayne Woollard ----- Original Message ----- From: wbuhles To: [email protected] Sent: Wednesday, May 21, 2008 12:29 PM Subject: [ercoupe-tech] Power failure on take off Hi Everyone; Had the time of my life last Friday. Just had my plane come out of annual where they found my old carb was shot and put on a spare they had and it supposedly ran fine. It has been doing well for about the last 4 hours I've flown it since the annual. During the annual they went through everything forward of the firewall and even had the engine off. All short of an overhaul. Well on Friday AM I loaded it up with full fuel and my suitcase and was going to fly from my home base at Yolo County, CA to Lompoc (KLPC), about 270 miles. Started up, taxied out, did run up and everything was fine, and then sat for awhile as two Bonanza's were doing touch and go's. So the engine was well warmed up. Started the take off roll and the output was normal, about 2200 rpm, felt OK, so I rotated and was about 50 feet in the air when the engine power abruptly dropped to idle, then caught again for 2 sec, then dropped again. I pulled back the throttle and put the nose down and landed, a bit hard because I didn't have a lot airspeed with which to finese, but intact. Luckily we have a long strip and there was plenty of runway still in front of me. Taxied back, put plane in hangar, drove to Lompoc. Before I put it away I did a static run up for about 30 seconds to max rpm and all was normal on either mag, no cough nor sputter, running smoothly. It is hangared, we have had no damp weather at all this time of year, and the tanks were full. I did not drain the gascolator sump in the engine compartment before I left. Thank goodness a past instructor had pulled the throttle on me once at about 100 feet and it was my instinct to lower the nose quickly. Likely saved my butt. Any comments or ideas on what it might be? I am thinking fuel contamination of some sort. One clue, before the annual the plane would start after about 4 pushes on the primer, and now it takes 8 or 10 pushes on the primer before it will catch and start. Cannot figure what might be causing that, but I know you guys will. Thank you in advance. Bill Buhles N94157, 415C
