When I was first buying my Ercoupe, one Coupe had low-mid-time engine and the other was at 1600 hours. The low engine time Coupe had some corrosion while the high engine time Coupe had none.
My mechanic advised me to buy the corrosion-free, high-engine-time plane and just figure the overhaul cost into my plans. "The metal inside the engine is 40 years old," he told me then (in 1978). Even a freshly overhauled engine can get a cracked cylinder or broken rod or whatever. So, I bought the high quality airframe with the high-engine-time and, after a few good flying years, paid for a quality overhaul to factory-new-specs a few years later. The last I heard, that plane is happily flying along on that overhaul. It must be near TBO again in spite of some years in storage in the middle. Remember that TBO includes both operating hours and years - 12 years, if I remember correctly. Ed
