I usually change my impeller every year in my Sherwood pump. Several years ago I lost one rubber vane and found it in the inlet port as well. Two years ago I lost one that I never found. I checked every hose, fitting and the heat exchanger and never found the missing vane. My only guess is that I might have pulled out when withdrawing the impeller and it may have fallen into some dark corner of my less-than-pristine bilge where may lie to this day.
I still get plenty of water flow from the exhaust and the engine operates at 160 degrees as long as I stay under 3200 RPM when Lake Erie warms up in July and August. Andrew Dalzell C-27 # 6298 "Tardis" Sandusky Bay
