Gary-
Thanks for the comments about the wash down pump! I'll try it out to see if there's enough volume from the motor with the idle rpm raised a little. C-Weed's comments seem to indicate there's quite a bit to be had with the Yamaha as long as you're careful to protect the engine's cooling.
I've actually wanted to add a wash down pump for some time, just really didn't want to add another system back under the transom to fiddle with, and since I boat in fresh water most of the time, I don't have the overwhelming need to wash great quantities of fish blood and guts off the boat. I already have electric pumped fresh water at the galley sink, but it comes, of course, from the 20 gallon tank and I can't waste it washing the boat.
If necessary, I might just build the pump into the covered slip and dock storage locker at the marina, going with a 120 volt pump and a small pressure washer. Would keep the system out of the boat, which has both positive and negative aspects to it.
I'm at the point after 6 years of ownership of the C-Dory that I'm running out of room for improvements, thus my statement a few months back about carefully considering each addition as you go along so as to not to have to get into the predicament of wanting to add something and not having any space for it or having to remove something to make space.
After a while, you begin looking for additions that serve and combine multiple uses to conserve space and eliminate complexity.
Thanks for the advice. Joe.