So I stopped the plane last time with 666.0 hours on the tach.
Went to fly a Instrument lesson, and broke the Carb heat cable…..Taxiied back and ordered a new one.
We replaced the cable…did a runup. now tach time is 666.4
Went to move it, and had a low tire (new this last February). Filled the tire and moved it to the hangar as it was too windy (+50 MPH) to fly. Did a complete warmup before putting it away. Tach time now 666.8
Taxiied out today for a lesson (tire pressure was still fine). During the runup, left mag showed a 300 RPM drop and lots of engine roughness. Leaning the mixture and running the engine up did not help. Taxiied down the runway to the nearest turnoff. Checked again. Engine now runs fine (apparently the taxi at more power/higher load/higher RPM was enough to get the plugs to cleaning temp.
Tach time? 667.0…
Coincidence? Or something more sinister?
Either way, did a 1.4 hour lesson and had nary a glitch.
Odd that the entire 666.X hour was gremlin prone though.