kaufmath

i'm definately learning a lot about my airplane in this process! gotta find the good in the bad. and its amazing how wide the differential on this problem is... I will take a look in the left tank, and painful as it is, I know the servo needs to go in.

Thanks to everyone again for all the thoughts. I'm making a list and will be checking everything twice. We successfully changed all the fuel lines (based on Mooney Support suggestion) today and cleaned the injector tips and flushed the system by engagin the boost pump which the injectors off. We caught the fuel as it came out in small cups, and there was some crud in each cup interestingly. My mechanic thought not enough to cause a failure though. I got brave and flew the aircraft after we worked on it (4th flight since failure all just above the airport). She flew perfect. Even the 'i cannot lean it to 650 anymore' issue went away now. the first three flights it would not lean to EGT's above 500. now it does, as it always did in the past. can a fuel servo problem BE intermittent? a friend at the airport suggested i contact the servo manufacture, which i thoght was a good idea too. bad enough to cause a complete failure yet perfect the rest of the time? i guess my understanding of the fuel selector is lacking, too. taking it apart would probably help that. so there is a difference between at the left tank position and clicking at the left tank position? selecting Right is always easy. selecting left in flight is always more challenging. oh and yes, fuel pressure stayed fine when applying power...the engine just stumbled each time i pushed the throttle at all. i've accidently taken off without the boost pump before without any problems. may have just been a coincidence as well. hate to think too that had i had it on, i might have gotten 1/2 mile further and ended up in a field or on I-75.

also, what problems have folks run into with the fuel selector that could cause this? thanks!

thanks for all the advice. fuel selector was locked on left tank. no bits of anything in gascolator screen and never a drop in fuel pressure. for fun, after it was running fine again, i moved the fuel selector to see how far towards OFF you could go before the engine would die. half-way between left and off, fuel pressure drops and engine sputters. i was no-where near that selection though the day of the event. we have all the fuel hoses off for replacement, and the fuel servo AD mentioned above investigated and does not apply. is there such a thing as 'vapor lock'? and if so, wouldn't the fuel pressure drop? i'm debating sending the fuel servo in for inspection, though it was re-built 5 years ago. cleaning fuel nozzles too.

If you read no farther, here's the main takehome lesson: use the whole runway...i almost didn't, and it saved my plane and my butt! As it is, I walked away with no injury and no damage. The question remains: why did it happen? My '78 M20J engine 800 SMOH failed on takeoff about 1 month ago. I'm still collecting opinions as to where the problem lies. Maybe you can help? It was a normal day in September, 75 degrees. Normal pre-flight including sumping but not gascolating, normal start, normal taxi-out, normal run-up. After normal lift-off at full power, at about 50 feet AGL, as I reached up for the gear handle, the power dropped to idle...basically nothing, though the engine did continue to run, just no power. I set back down, scared but unharmed. (always fly the airplane!) So safely back on the ground, the engine will idle but ANY addition of power and it wants to quit altogether. Every gage was in the green, no loss of fuel pressure. Of note, I did NOT have the boost pump on during the takeoff as I usually do that day. Half tanks that day. So I shut down, pull the cowl with local mechanic and find nothing on gross inspection. Restart...same thing, it will idle but not take ANY power or it wants to die. Boost pump has no effect. Trying to lean on the ground does NOT lead to my typical normal slight increase in RPM. After 5 minutes of sitting at idle wondering "what the heck", I change from left tank to right tank, and within 10 seconds problem goes away COMPLETELY. She takes full power, runs fine, and re-switching tanks will NOT reproduce problem. She had been on left tank from previous flight 1 week earlier, a flight which was turbulent, but otherwise uneventful. So several runs up and down runway and ultimately 3 flights over airport, and it runs fine now. Cannot reproduce the issue. No debris in gascolator, no debris in throttle servo screen, no stuck valve, no problem in exhaust system found, and absolutely no water found after rechecking 10 times. Not a drop. The only thing I notice is that if I try to lean out a bit at 3000 feet while circling the airport, the EGT (single cylinder only) temp does not come up nearly as high as previous...seems like a clue. I haven't dared leave the pattern though. If this way your plane, where would be the top 2 or 3 places you'd be looking now? Any help is appreciated.