Fluid question.
 

I have a 4.3L in my 1994 Barchetta. This is my 3rd boat but the first inboard outboard I've owned. There is a drive oil reservoir located above my power steering pump. What oil do you use and how often should it be changed?

Since this is my first I/O are there any good books on maintence?

Most marinas / boat supply vendors etc sell a Mercruiser manual for $35 (Cdn) or less. The gear lube is Quiksilver High Performance (it's green in colour) but there are other options such as a synthetic Amsoil 75w-90 or similar Pennzoil. Just dont mix the different brands. Changing it once / year is a good practice.

Since you're a contributor, the best resources for you is located in the Service & Repair Manuals section of the site, the Official Mercruiser Service Manuals! There's a seperate service manual for the Alpha Outdrive, and then the service manual. For Fluid specifications and such, check the first section of the service manual, called "Important Information". It's all located in there. Download whatever you need!

Thanks for the info.