A sea doo tech here told me that the pump grease (comes in a small tube) is the only grease that MUST be used in the nose cone. He said something about it becoming less viscous under operation.
The synthetic grease though I am not sure of.
Would love to know if one can use this grease or just plain spray marine lubricant on the bolts to prevent them from seizing in salt water. I removed my jet pump yesterday after 25 hours of operation and the bolts were a b!tch to remove. When I eventually got them out they were covered in salt corrosion.