I've got an Aquamedic Ocean Runner 3500 pump that keeps dripping slowy
(1/min) from the O-ring seal. Tried vasoline etc. but has not helpful. The
O-ring is not damaged, but I have not been able to find parts for this so
that I could even try another.

Is there some trick to stop these damn O-rings from leaking? I've had this
problem before on another different pump too. Seems like they should put
double O-rings on these pumps. Single O-rings are just not enough.

Any suggestions.

Chris.