Nautique overheating

Ok, I have a 1982 Ski Nautique that just started overheating. I figured the impeller had gone bad, which it did, so I replaced it. It still overheated. Then I figured that the thermostat had stuck and gone bad, so I switched it, yet the motor still over heats. I have a water hose adaptable water intake so I'm doing this all in my driveway, and I noticed that when I rev the motor up, not as much water comes out the back as it did a week ago. I'm now thinking that a line is clogged somewhere, but I'm not sure and I thought I'd see if anyone here has had the same problem. Any and all help is appreciated and as always- thanks in advance.

I don't know if this applies to you, but when I run my boat off a waterhose in the driveway, and rev the engine, the boat requires more water than the hose can supply. I usually run by connecting a hose to the water intake, and putting the other end in a 5 gallon bucket. I tnem place the bucket under the exhaust port, and reclaim the water out of the exhaust. I have never had an overheating problem doing it that way.

Now if you have run the boat like you said, and it has just recently started overheating, then you might have a bad sensor.

check the line from the trans cooler to the bottom of the impeller housing. Also check the bottom of the impeller housing itself to see if chunks are still in there.

Make sure after you replaced the impeller you didn't re-install it's housing upside down. My friends and I did that on a '90 sport nautique by accident...we checked everything and then someone finally realized what had happened and after a switch no more problems...sounds stupid, but it happened pretty easily w/o detecting it.

I second DJL's suggestion. If the impeller was in really bad shape when you pulled it, there may be some leftovers in there restricting flow. If they're not where DJL suggested, contact the guys at skidim.com. They will hook you up with other troubleshooting advice.

My guess is that your water seperator is leaking, bypass it.

Let's make that water filter...

It was in fact what Patrick and DJL suggested. First, I checked to see if I had installed the impeller housing upside down, which I did. Second, I went through the transmission cooler line to find only a couple of very small chunks of old impeller imbedded in it. I flushed all the lines out and put it back together and whaddya know, the boat works now, or at least I hope so. I'll be going to the lake this evening to try it out. Thanks again for those who helped out.