Recently purchased a 23hp go devil to put on my 14 ' xpress. I am going to cut down the transom from 20my to 16 or 17 inches. I am new to mud motors and was wondering how and if I need to adjust my capitation plate? Also is it possible to have spare keys made for this motor? Or are they a one key fits all sort deal like a CAT for example?

Most lawnmower places have keys for Briggs, Kohler, Honda and so on. They are cheap so get a couple and put them on those little float fobs and you are done. Cutting down the transom will work. Adjust the plate in small increments of say, 1/4" at a time. If the prop kicks out too much, bend the tab up; if it is too deep, bend down. I would advise making or getting a "trim tab" like MB fits on their LT's- these are easier to bend/adjust than the main plate and work. You will also note how you carry your load will affect performance- I had to relocate the battery (and/or gas tank) to the front to get better planing, but each hull is different. Any wear,etc. on the prop, as is often stated on this site, will greatly affect performance. Your elevation may also dictate your optimum prop size- my 27 HP runs better with a 9x6 than the mfg. indicated 9x7. Hope that helps. Let us know how it goes!

X2 - on all that and I would add that prop wear is the biggest single issue IMO....

A worn prop has lots more "lift" than a new or good prop....

I liked the 9x6 best on my 23 GDLT too and can tell you that by the time the prop
diameter had shrunk to 8.5" that lift was very noticable and raw power was
baddly reduced even though WOT speed was still pretty good....

I would suggest you invest in a new 9x6 - no matter what and save the original
as a spare as soon as your budget allows....