90 Mariah Vibration in Forward not Reverse

[remodrums33]

I just purchased a 90 Supra with a PCM 351. When operating the engine on the trailer, there is a harsh vibration when forward is engaged. However it does not occur in reverse. I have only owned Mercrusier drives and they never acted this way. Is this happening because it is out of the water or do I have a real problem? The vibration appears to be coming from the prop shaft support just forward of the rudder.

[beast 496]

Lubricate the strut brg and stuffing box is you are running out of water. If you leave run too long with out lubrication it will damage the strut brg. Note the strut brg is a brass core with a rubber bushing. Rubber on Stainless steel will build heat extreamly fast with out lube. Al

[michael hunter]

The trans will move the prop even in neutral out of water . As beast said its because of no water lubricating the prop shaft it vibrates. I always jam the prop shaft at the coupler with a wrench so it cant turn. Also dont put it in gear when its blocked like that.