This is all about installing Perko FlushPro kits on my Cruisers. Most people install these to flush-out their engines after a day in the salt, which is partially true in my case, but my real reason for all of this was because I wanted to start my winterizing early. Two-months early.
Let me be the first to say I know installing the FlushPro may be a bad idea on the genny. My genny sits lower than the thru-hull exhaust port from the high-lift muffler. If the genny’s impeller fails and I feed it 60PSI water from the dock, I’m probably going to have a bad day the next time I try to fire-up the genny. I’m likely going to add a ball-valve on the genny-feed at some point soon, to prevent such a problem in the future.
<<update May 2015: Looks like I never came back here and updated this post… turns out, running a FlushPro to the genny WAS problematic after-all, see update below for more information…>>
Installation wasn’t cheap. Between the kits and about 5-trips to WestMarine to get more hose, clamps, fittings, etc, I’m guessing North of $400 by the time I was done, plus lots of hours too. That’s okay, though… it’s a labor of love.
Installation is straight-forward, no real surprises. Everything works like you’d expect. Pull the deck, cut the lines, use 50 hose-clamps, then cross your fingers. Setup worked great, though my setup only feeds enough water to run one engine at a time from the garden hose (I’m actually happy with that, because of over-watering the genny as discussed above).
I used these Perko’s for probably 5-hours before the end of the season. They actually worked GREAT in the boat-yard while on jackstands… ran the genny for a long time like that. In fact, high-and-dry use of these FlushPro kits is probably their best selling point for me.
Here’s what I did:

Pulling the deck for engine-room access

More room with the deck out!

One of the Perko FlushPro kits

The genny's Perko installation

Port-side FlushPro before waterline connection

Starboard-side FlushPro install

Cut a hole in the pretty gelcoat

Update May 2015: There are TWO fill-plates now; left feeds both engines, right feeds the generator only…
<<update May 2015: Turns out the diagram below wasn’t the final install. One transom-plate feeding BOTH engines was okay, but ended-up being dangerous to include the generator as-well. The problems were two-fold:
1) with the engines running, there wasn’t enough water flow to the generator, and
2) if the generator impeller was bad (like every single spring-launch), city-water would bypass the generator’s impeller
Where this becomes serious is, the generator’s muffler requires the generator to be running to pressurize exhaust, because of the high-lift. If the Perko FlushPro is allowed to flow for very long (20-seconds) with a bad impeller without the genny running, the water pressure builds up enough in the muffler to back-fill the generator’s piston through the open exhaust valve.
In the end, I ended up installing a second fill-plate, dedicated to the generator only, so I could monitor/control city water flow while paying attention to the generator specifically…>>

Updated May 2015 to show the final version, the genny required its own fill-plate, to reduce risk of pressurizing generator exhaust when not operating

A look at the finished port-engine FlushPro