Brockster
Well Known Member
Have been trying to help a friend troubleshoot a Lycoming O-360 / McCauly constant speed prop combination on his Cessna 177 Cardinal. Engine rpm varies approximately 100 rpm or so while in cruise flight. Creates a definite hesitation while flying. There does not seem to be any pattern to it as it comes and goes sometimes 30 seconds or several minutes between occurances. The occurance only lasts a few seconds. Occurs also at reduced power settings but tends to be less severe. Manifold pressure and oil pressure are solid before, during and after occurrances. Mag check on the ground and in flight are both good. In flight with either mag off does not stop problem. McCauly prop currently installed was brand new and has only a couple hundred hours on it. Previous McCauly prop which could not be overhauled also had the same problem. Original McCauly govenor overhauled and did not help. Switched to newly overhauled Woodward govenor and again did not help. Accomplished Lycoming Service instruction #1462A, Propellor oil control leak test procedure and no findings. Mags have been torn down and checked per overhaul manual and nothing found. Spark plugs and leads tested with no findings. Really starting to scratch my head as to what the problem could be. Any suggestions would be greatly appreciated. Problem has been there i'm told for some time but never gets worse or better. Engine has 1750 hours with New ECI cylinders 325 hours ago. Will be trying all new plugs but after that I am out of ideas.