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Thanks, all, for replying.
In reply to Jerry, the alternator was in fact seized and the Lord coupler gave way, sparing the shaft from shearing and the potential of metal fragments navigating around inside the engine. Believe it or not, that alternator just came back from repair under warranty and was re-installed just before my son and I left NH for the Bahamas. What kind of repair they did, I can't imagine. Obviously, the bearing was getting ready to go when it left the shop. The alternator light came on steady while we we out over the ocean (where else?)between Fort Pierce and Freeport.
Re my separate problem with fluctuating manifold pressure when RPM is pulled back below 2500, no the problem has not been solved. My mechanic has searched high and low for leaks and swears there are none. I believe him. And he has examined the waste gate controller and waste gate for proper operation.
I think I gained some insights into the problem on this trip to the Bahamas, however. As we flew south and air temperature and humidity rose the oil cooler became less efficient and oil temperature rose, while oil pressure fell. The rear engine oil temparture climbed to around 210 and pressure fell to 47. I had to open cowl flaps partly and run richer than normal to control the situation.
How do I know the oil pressure was 47psi? Obviously, I wasn't getting that info from the crummy Cessna instrument. No, I just had two Electronics International UBG16 engine analyzers installed, that show, in addition to EGT and CHT, oil temp, oil pressure, volts and amps. Wow, it's great to know what's really going on in the engine compartments. I love these analyzers.
I recall my mechanic said the maintenace manual states that a minimum oil pressure of 51 psi is required for proper operation of the waste gate controller. So it may be my problem is one of oil temp and pressure. I've been running 15w50 oil, but I'm having that changed down here to 50w non-synthetic. If the test flight shows oil pressure still low, the mechanic is going to adjust the oil pumps to increase pressure. I hope one or both of these measures wil solve my problem with MP. It would be great to fly home to NH from Ft. Pierce at FL 200 and catch some tailwinds for a change, with a stop in VA or MD, depending on the winds.
Another altnernator is on the way, arriving probably in three days. This time it's 38 amps.
Meantime, I'm still marooned in the Bahamas, missing all that snow and ice at home. Sigh.
Best,
Gordon
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