And yet another temp question - 1992 SN

[chill99]

I've read lots of posts on this, but I think my issue is a little different. Looking for opinions on what to try.

I bought my 1992 SN a couple of months ago. I've used it at the lake a few times with no problems. The boat is in great shape and runs great. However, since it's new to me, I wanted to do all the typical maintenance so I know the status of such things. Therefore, one of the things I did was change the impeller. Turned out to be a good move because the old one had a torn fin, but it was still all intact.

After changing the impeller, I took the boat out and the temp jumped up to 200+. Prior to changing the impeller it ran around 160 - 170. So I decided to change the thermostat. I put in a 160 t-stat (proper one according to Skidim.com). While doing so I found some pieces of impeller in the t-stat housing. So I cleaned that out real good and looked closely for more pieces. I also changed out the temperature sensor just because it's cheap.

Now when I run the boat it's running at 180 - 190? I'm really confused. I've checked all hoses clamps and they are tight. I've checked the water filter and it's tight. No leaks. I rechecked the impeller to make sure those parts weren't from the new one and it's just fine. I don't know what the temp rating was for the old t-stat - I couldn't read it because it was pretty old.

Ideas? (sorry for the long post)

[DavidF]

RE: And yet another temp question - 1992 SN

Air leak before or at the RWP?

[chill99]

RE: And yet another temp question - 1992 SN

Update...
I've gone thru and checked every hose connection and made sure they're tight.
I flushed all hoses looking for old pieces of impeller - found none.
I pull out all drain bolts looking for debris and found none.
I checked water strainer for cracks & checked o-ring - everything is fine.
I put the old temperature sensor back. Also did a test from skidim website to test gauge - all is fine.

All this and my gauge still shows 180 - 190?

Next thing to try is a new gasket in the impeller pump. I changed the o-ring when I put the new impeller in, but not the gasket. Just making sure there are no leaks there. Then I'll probably test to see if the pump throughput is high enough.

I'm thinking maybe the old t-stat was a 143 and now I've installed a 160. But still, shouldn't my temp gauge show 160? Skidim website says if the temp is steady, there probably isn't a problem. Thoughts on that? Is 180 - 190 bad, assuming that is the accurate temp?

[Rick]

RE: And yet another temp question - 1992 SN

At this point the thermostat is mute. It is open all the way. The thing that makes an engine run hot is lack of cooling water this is caused by air leaks that cause the water to flow or impellor problems or blockages. Sometimes the impellors will twist on the shaft. I would try another new impellor first. you can run an engine for several minutes without water you may want to take the outlet hose off the RWP and see if it pumping. i would bet on a bad impellor or missing key in the RWP Good luck

[darrel409]

RE: And yet another temp question - 1992 SN

is there teflon tape on thethreads of the sending unit? Can cause the gauge to mis read. I run a 160 t-stat too, at idle temp may increase but goes right back down once moving.

[chill99]

RE: And yet another temp question - 1992 SN

Today I went thru everything again and more.

darrel409, thanks, there was teflon tape. I cleaned the threads with a wire brush. I rebuilt the impeller pump again, this time replacing the paper gasket. I also did a flow test as suggested on skidim.com. The impeller pump put out 5 gallons in 15 seconds running at 3000 rpm - just like the site said it should.

Rick mentioned bad impeller. It's new and when I rebuilt the pump again, I verified it was still ok. Key is also there and ok. Plus, if it's putting out 5 gallons in 15 seconds, I'd say that part is working ok.

All that did help some. At idle speed in the driveway (with plenty of supply water) it's running at 180. I guess I'm hoping that running it around the lake it will be cooler. But it still seems like it should idle at 160 or just a little over.

Could the gauge just be old and out of calibration? Or could the new thermostat I put in be defective? That the only two explanations I can come up with at this point.

Thoughts anyone?

[Rick]

RE: And yet another temp question - 1992 SN

Try taking the thermastat out completely. The boat then should stay below 160 the whole time. If not there may be a blockage in the manifolds or somewhere else that is restricting flow. The thermastat is there to let the engine warm up to the correct temp. If it is bad it would be causing the restriction.

[bobchris]

RE: And yet another temp question - 1992 SN

he using a 160 t-stat and the engine is going to run about 20 degrees more than the t-stat you use, there realy isn't a problem on a lack of knowledge and thinking there's a problem when there isn't one.

[efox]

RE: And yet another temp question - 1992 SN

There probably is not a problem, but it is disconcerting. The other thing you should be aware of with this model and year is the dash wiring is not good. It is likely that your ground may be weak. Do you notice the gauge move if you tap on it's face? Mine does this, and the reality is I need to clean/check my grounds on the dash or create a whole new one for that guage. Again, my experience is that the wiring is not really up to par and the connections are only spade connectors which are prone to corrosion.

Eric