SoonerFan, I like that "half snoot", not sure if it's a good fit for a 21 though, looks like a pretty sweet setup. Tom (JBP) will probably chime in soon, but I'm thinking that snoot may be hurting you, I have only had good luck with snoots on really light "flighty" hulls, on the other hand I have heard folks having good luck on larger boats, just not me..
I would do some more testing and maybe as a shot in the dark have it weighed. Also as Stevecat says, make sure there isn't 200' of rope around the impeller shaft LMAO.
GT