Jimmy, it's a shot in the dark but a GREAT bud of mine that has run Yammies for years on his Allison's and he and his wonderful wife Ms. Linda are owners of Lindas Lakeside Marine up on Cherokee Lake over in Morristown, TN. (I bought my XB-21 from them) Give him a call, if he doesn't have it he is likely to give you several names or places to look up!
http://www.lindaslakesidemarine.com/