[Lillikat]

There are two large strainers and seacocks for the engines. There should also be 2 smaller ones for the generator and the A/C pump. Look close to the units to find them.

In the GPS check with Max Marine Electronics on the web. They sell used/rwbuilt and will also take your unit in and rebuild it. They are good people.

Thanks Sans. Will look into it further. 

Re: GPS I'd love to switch out to touch screen units without overhauling entire electronics system. I can prob talk to the max marine guys about that.

Any idea how to find amp/subwoofer in 3900?  Not in owners manual and wiring diagrams are another language for me.