I have a Venture 60 and cannot get the flutter out of it.
I have a OS 61FX on it. I have worked on the plane for 3 weeks
doing all the normal suggestions to stop it. I sealed the ailerons
and I sealed the rudder and elavator. Nothing seams to
help. Any suggestions.

Have you checked your control linkages? If there is play in any of them your flutter could be coming from that. Just a thought.
Rj

...are you using solid pushrods, or the "nyrod" type? The solid pushrods should not translate to flutter, however, the nyrods can flutter if additional bracing was not used every six inches, or so inside the fuse. This is presuming that all other linkages are slop-free.

Try using a rigid linkage and/or a stronger servo.

Stiff linkage and stiff structure. If either the surface structure is flexable or any slop in the linkage or small diameter push rods you can almost garantee flutter at high speed.

If the above suggestions don’t take care of the flutter try counterbalancing the control surfaces.