I've recently bought a newly built RV-14 with a -EXP119 engine, Hartzell HC-C2YR-1B prop and Hartzell S-1-79 governor. It has just about 25 hours total time on all. When I test flew and brought it home everything with the prop was working fine but then it become very sluggish when cycling the prop on preflight and inflight. The oil level started at 7 qts when I first bought it but had gone down to about 5.5 qts over about 8 hours. At 5.5 qts the RPM and oil pressure was hardly changing at all when attempting to cycle the prop on the ground. I filled the oil to 7 qts and it's fine again. The Lycoming manual says oil quantity should be between 7 and 3.5 qts. Any idea why it seems to need more than 5.5 qts to control the prop correctly?