Thanks to everybody for their replies. This has never occurred in the last 10 years and I feel it is simply due to not running the engine for three months and difficult to move the oil back up to the tank because the temps were in the 50's. I normally fly on a weekly basis and never go longer than two weeks. The plane is a Rans S7 and the oil tank is mounted within the specs from Rotax. Roger made mention that I probably have an older style oil filter, I know they have a newer style and I believe it has a "check valve". I assume this "check valve" would stop the draining of the tank into the crankcase.I will look into that. I always hand prop the engine at least 10 revolutions before starting and am aware of hydro-lock in an engine.
Okay, today I removed the hose from the bottom of the crankcase and drained about 2 quarts of oil and put it into the tank bringing it almost to the top mark. Pulled the plane out and cranked it up. Oil pressure went immediately to 70 lbs and never moved much from there, Apparently there was no air in the system. Then went flying for and hour or so, no problems there either.
So another problem solved in the Experimental Learning process, it has been ongoing since day one.
Dale
