Help overheating

put running water near the rwp,at the shaft, if its pulling air this trick will clear it momentarily, you may have to do this for a few minutes for the temperature to regulate, the shaft seals are commonly overlooked and if pulling air will turn the water into airiated water which does not transfer heat

I have an 83 correct craft ski nautique. On the hose at home eng runs fine... Normal temp, (I hypothesized this is from my house water presser pushing water through-ought the system)... put it on the lake and temp shoots up over 230. I have a t.stat that is 160 for PCM. I have tested the water pump and replaced the impeller, tested each connection for possible air leeks with neg/ results. Systematically using a 5 gallon bucket and timed the time it takes to drain the bucket approximately 20 sec @ 2500 RPM. The only thing I can think of is that my skimmer top is linking air into the system if there is any one with a PCM Ford setup like my 83, can you look and see if the skimmer has an O-ring for the top and is so any ideas if this is my problem since I have excluded the water pump as being my problem.. Thanks Rob