Thanks. I used JB Weld. Success for now it seems. It's sure a huge pain in the a$$ to get those washers and wingnuts on from the back, esp. the middle and front ones. Tried unsuccessfully to completely remove the panel from the boat, wasn't confident enough to disassemble throttle control far enough to achieve that, oh well.
2001 ProStar 190 EVO, LTR 330