I have a Force 120 that is overheating - buzzer going off at lower speeds - but water still coming out of upper part of motor. I had the lower unit replace last fall. I believe the problem to be the impeller and have ordered the replacement kit hoping I might be able to handle this project. Bigger problem is I'm a total novice at this and don't want to start something that I will cause more damage. I have the Force Service Manual and have been reading up. Any advice or help would be greatly appreciated.