My 1988 DT150SS was finally running great. I cleaned and rebuilt the carbs, that helped a little. Then I put in a new throttle position sensor and that did the trick. The motor was running perfect. That lasted for two days, and on day three, at about 3/4 throttle and going fast, I trimed the motor up like I always do on my bass boat. The second I hit the buttom my rpms fell dramtically. It became harder and harder to get on a plane over the next two days and now it wont do that. Any ideas? Another note is that my tachometer is also being very erratic, but I'm not sure if that's a realated problem or not. Thanks for your time. I really aprreciate anybody willing to help with any advice.