I have a 1986 Chris Craft with a 140 Johnson on the back. I got the boat for free and after no knowledge of its history and 2 years of cleaning and getting her back running, I have taken her out for 2 rides now and I have a couple issues. First off when I left the marina and after about 30 minute no wake zone, I gradually give it some more throttle and after about 30 seconds, overheat alarm goes off. One of the first thigs I did was replace the impeller. So I did some investigating and found that the plastic thermostat was melted on one side of the motor. So removed both of them for testing for my next trip out. And by the way it will never overheat in the driveway. So I head back out again a few weeks later and same issue, I walk to the stern and it looks as if the intake on the outdrive has no water reaching it when the motor starts to gain speed and thus overheats. I looked at the shaft length and it seems to be proper length with the cavitation plate a couple inches below the bottom of the boat and as far as I know it is the original motor. One thing I did notice was there were holes drilled into it for one of thos "whale fins." Would one of those fins keep the water down enough in a situation like this? I am lost.
