Narrative:

Departed hqm on an IFR flight plan to bfi. I requested and received clearance for a VFR climb to 7000, engine sounded normal on takeoff and climb out, but was slightly sluggish. Cht, egt, manifold pressure, and RPM were all within normal range. Approximately 20 northeast of hqm engine started to miss slightly. Carburetor temperature was plus 10 degree C, but full carburetor heat and full rich mixture helped. Cht then started slowly climbing and any attempt to lean mixture or push in carburetor heat resulted in engine missing worse. I then advised ATC of the problem and was cleared direct to tfw, which was closer than bfi and also the aircraft home base. The remainder of the flight, the visual approach, and the landing were all uneventful. The reason for this report is that this is the second time since the aircraft received a supposedly thorough ($2800) annual in june that I have had to divert for an engine miss. The first time was due to a bad coil and bad bearings in the right magnetic that the mechanic admitted should have been caught at the annual. Now, 2 flight hours after the mags were rebuilt, I have another problem. The aircraft was trouble free (engine wire) prior to the annual. I think the problem and I have encountered this at each shop I've tried, is that the quality of work afforded to GA aircraft I just not up to standards. Whether the cause is a shortage of mechanics, or economic pressure, or whatever, this situation is dangerous and will (and probably has) resulted in tragedy.

Related reports:

Google
 

Original NASA ASRS Text

Title: SMA DIVERTS AND LANDS WHEN HIS ENG BECOMES ROUGH.

Narrative: DEPARTED HQM ON AN IFR FLT PLAN TO BFI. I REQUESTED AND RECEIVED CLRNC FOR A VFR CLB TO 7000, ENG SOUNDED NORMAL ON TKOF AND CLBOUT, BUT WAS SLIGHTLY SLUGGISH. CHT, EGT, MANIFOLD PRESSURE, AND RPM WERE ALL WITHIN NORMAL RANGE. APPROX 20 NE OF HQM ENG STARTED TO MISS SLIGHTLY. CARB TEMP WAS PLUS 10 DEG C, BUT FULL CARB HEAT AND FULL RICH MIXTURE HELPED. CHT THEN STARTED SLOWLY CLBING AND ANY ATTEMPT TO LEAN MIXTURE OR PUSH IN CARB HEAT RESULTED IN ENG MISSING WORSE. I THEN ADVISED ATC OF THE PROBLEM AND WAS CLRED DIRECT TO TFW, WHICH WAS CLOSER THAN BFI AND ALSO THE ACFT HOME BASE. THE REMAINDER OF THE FLT, THE VISUAL APCH, AND THE LNDG WERE ALL UNEVENTFUL. THE REASON FOR THIS RPT IS THAT THIS IS THE SECOND TIME SINCE THE ACFT RECEIVED A SUPPOSEDLY THOROUGH ($2800) ANNUAL IN JUNE THAT I HAVE HAD TO DIVERT FOR AN ENG MISS. THE FIRST TIME WAS DUE TO A BAD COIL AND BAD BEARINGS IN THE R MAG THAT THE MECH ADMITTED SHOULD HAVE BEEN CAUGHT AT THE ANNUAL. NOW, 2 FLT HRS AFTER THE MAGS WERE REBUILT, I HAVE ANOTHER PROBLEM. THE ACFT WAS TROUBLE FREE (ENG WIRE) PRIOR TO THE ANNUAL. I THINK THE PROBLEM AND I HAVE ENCOUNTERED THIS AT EACH SHOP I'VE TRIED, IS THAT THE QUALITY OF WORK AFFORDED TO GA ACFT I JUST NOT UP TO STANDARDS. WHETHER THE CAUSE IS A SHORTAGE OF MECHS, OR ECONOMIC PRESSURE, OR WHATEVER, THIS SITUATION IS DANGEROUS AND WILL (AND PROBABLY HAS) RESULTED IN TRAGEDY.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.