Hi Steve,
I’ve been thinking about your email and thinking back to all of the Pipers I’ve flown over the years and I think I have an answer for you. While I’ve flown Seneca’s (TSIO-360) for the last twenty years, I have thirty years before that flying Cherokees, Arrows, Seminoles,Mooneys, Grumman Tigers and a few other planes that I can’t recall at the moment. Here is what I think may help you.
If you think back to when these airplanes were designed and their POH’s written we go way back to the 60’s. Heck, I just retired and I was in High School when your airplane was built! In those days there were no computers. Everything was done by estimation and slide rule. So my guess is that Piper chose numbers that erred on the conservative side. I doubt seriously if the exact RPM’s specified in the manual for run-up are all that precise. Whether you use 2000 RPM or 2300 probably doesn’t matter. Also, when leaning I would start at the 3500′ level just as you’ve been taught. Having said that, keep an eye on your cylinder temps. On hot days it may be prudent to be full rich. Don’t forget, extra fuel cools the engine.
Thanks for writing your question to the PFA forum. I hope that other members weigh in on this topic also.
Keep the blue side up,
Scott Sherer
N344TB
