The MS25S-A was a sail drive that Volvo Penta used to put behind the MD2020-MD2040 engines. It always
created big confusion as there is are a couple of inboard gears (such as the MS25L) which have almost the same name.
The MS25S-A was around for a couple of years and then it transitioned into the 120S-E saildrives which in turn later became the 130S saildrives. Matter of fact the lower unit of a MS25S-A and the 120S-E is the same. The upper unit of the MS25S is unique however.
If you try to purchase an MS25S-A now it supercedes up to a 130S saildrive which has a retail value of $7,920.24.
Back in the day the MS25S-A sold for about $4,800 or so.
But there are a passel of them out there so you should have any trouble selling it.
I received this new sail drive unit in with a group of transmissions. It is complete in the original container.
Let me know what it is worth.
See attached pictures.