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huston marlowe

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I know this is not an easy question but any experienced opinions might help. I have been operating my C-85 powered J3 for 11 years and have always wondered if the vibration/shaking was typical. I have a few hours in five different Lycoming powered machines and they seemed smooth as I remember. This Cub is the only Continental powered ship I have flown. I have tried a different prop and changed out the rubber cone mounts...no change. When I had to replace the valves in one cylinder the first take off really got my attention with serious shaking but that smoothed out over time..I suspect the new valve stem/guide was sticking a little. Engine does not use oil and has 80/80 compressions. Oil pressure is at the low end when hot but really the thing has not changed in any trending way during the last 300 hours or so. It just makes the windows shake . I will be selling this Cub within a year and will be breaking in a overhauled C-90 in the project Cub. Just wonder if the new engine will shake too !! And wonder what to say to the new owner of the one I sell .Thanks !
 

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