Still overheating after clearing debris

[tman]

Boat: '97 2150 Scorpion.

I recently replaced my impeller and found debris from a prior impeller in the housing. I cleared the housing and also cleared the tranny cooler(which was full of debris). I put the belts back on, ran it for a while and it began to overheat again(the temp gauge would jump from 120/140 to 160/180 very quickly back and forth). I pulled the housing and impeller out to make sure that more debris did not clog; however, I found nothing. Then I pulled every conceivable hose to make sure debris was not there. Still nothing and I am at a loss. I even pulled the hose running through the fuel cooling housing while in the water at my dock. I don't know what level of flow should run through but it did not seem like a lot. Could it be a temperature sensor???

Any help is greatly appreciated.

[chpthril]

May be a faulty thermostat or a piece of impeller/debris lodged in the thermostat? Or a blockage in the main waterpump. Good luck, I hope you get her fixed soon.

[lee]

Is the housing warped or burnt on the inside? My need a replacement.

[tman]

Thanks, I have not changed the thermostat before and that seems like a likely cause. Where is it located?

[tman]

Lee, the housing looked like it was okay but I didn't examine all that hard. I will check it again to make sure.

[TeamAllen]

I recently had to replace my circ. pump. It was weeping rusty colored water from the weep hole underneath.

[FIC]

Follow the hose coming off the pump going to the top of the engine, pull it off of the top which should be the thermstat housing , start the engine with the water flushing unit hooked up and water on you should see some major water flow if you dont than you need to check your hose hook ups or impeller rotation.

[Razzman]

Tman, start with your themostat after you've double checked your hoses for obstructions. A thermostat is easy to replace and cheap insurance. Make sure to get ALL of the old gasket materials off of the housings before you re-install. It's not uncommon for them to wear out over time as the spring looses tension after repeated cyclings.

[tman]

Thanks Razzman, will do!

[mainiak1]

tman

I had my temperature fluctuate like yours before. It turned out to be airbound. The problem would go away when I took the boat for a spin. Then it would return after 15 to 20 minutes after shut down. My problem ended up being a bad check valve on the cold water to my shower line. It would drain the water in the block back to the lake. Check to see if you have some type of leak. After I thought about it when I changed the thermostat I now realized there wasn't any water at that level.
Good luck.

[tman]

Razzman, I took your advice and started at the thermostat. The old thermostat was rusted out and corroded and so was the old gasket. I was lucky that I had a razor blade handy from removing an old sticker. It was useful in pealing/scraping the "cooked" gasket. I did learn my lesson though when I didn't clean/scrape all the debris because I when I put it all back there was a leak due to too much space between the gasket and thermostat housing. Once I re-cleaned, it is good to go. All in all it is a cheap and easy fix. I noticed there was a little temp. gauge fluctuation but it normalized. I also notice the sending hose to the right manifold was VERY cold and the one to the left was cool. However, I turned off the motor and waited and could not get it to turn over. I waited a little longer and it finally started. Could the gas be turning to vapor or is it a connection issue (distrib. or spark cable).......? Aaaargh.

[dogbert]

It might have had something to do with our weather, we had over an inch of snow at the lake

Did you check the water coming out of the exhaust or just touch the hoses? Did you ever run the engine above idle?

Given our recent temps, it would take a long time to warm up the hoses.

[tman]

No Kidding Dogbert! We got sleet yesterday and my girls were a little chilly headed to church this morning in their Easter dresses! Anyway, I don't think it has been hot enough for vapor lock, so I think I need to change the fuel separator first and then check iginition components(distributor/rotors/cables). Any suggestions are appreciated.

[Razzman]

Tman that's exactly what i would do. How long has it sat? I'd check all your connections and the condition of all to include the ignition components. I gather yours is carbed as mine is? If so double check the nuts holding the carb on as well, sometimes they loosen over time.

[chpthril]

May be a faulty thermostat or a piece of impeller/debris lodged in the thermostat? Or a blockage in the main waterpump. Good luck, I hope you get her fixed soon.

Razzman, I took your advice and started at the thermostat.

What am I here, chopped liver

I turned off the motor and waited and could not get it to turn over. I waited a little longer and it finally started

Are you saying that the starter would not spin the engine or that It would crank over but not start (run)?

If the starter is not spinning the engine over, it sound like a leaking exhaust riser allowing waster into the exhaust and into the cylinders and hydro-locking the engine. Water cannot be compressed and there for the engine will not spin over.

Like Dogbert asked, did you check to make sure you had water flowing out the exhaust? If the enging temp is stable and w/in the normal range and water is flowing out the exhaust, then I think you have fixed the circulation problem.