Suzuki Outboard 32800-89J11 Rectifier & Regulator - Browns Point Marine Service, LLC
http://www.**********/parts/search/Suzuki/Outboard/2003/DF25/RECTIFIER/parts.html
NOt as high as 240....
Generally, when any electrical part fails, it is due to an excess of load, either a voltage spike in excess of it's ratings, or a current load in excess. That's in general.
So, whenever a rectifier blows I look for too much load on the rectifier circuit, and that usually translates to a bad battery.
Battery gets old, sulfates up the plates, takes more current to even keep it charged...etc. Rectifier works extra hard for extra long, generating heat, just to try to keep the bad battery charged up.
When you put the new one on, use a liberal amount of heat sink grease between the reg/rect and the block for good heat transfer.
Also, that's air cooled....you have a good unrestricted airflow around it? I know it's under the electrical plastic box...but you sure it is being cooled well enough?
That's what I look for anyway.
EDIT: I see the website blanks out competing online parts merchants. I think you should be able to get this reg/rect for about $160.00.
Look around some more.