A friend of mine has a twin engine Chaparel Cruiser with 350's and alpha 1's. One of the drives looses a whole reservoir of drive fluid in about 40 miles. The boat can sit on a lift and not loose a drop for 4 months. No fluid is collecting in the bilge . Any thoughts?

Chris

Prop seal? It has to be going out so either that or an outside seal. Still should have some water in resavoir after a good run if not it's a bad leak and all just going out. Pull filler screw on bottom probably full of water.

Input shaft seal us gone and dumping the oil into the shaft bellows.
Just cost me $1k for the seal, bellows, gimbal bearing, ujoints and seal carrier.
I had the same problem.

Its probably the propshaft seal or input shaft seal as described.

I have also seen shift shaft seals leak & it looks like fluid leaking from the water intake ports

fix now....the pin has been removed