overheating problem

[H20skeefreek]

Hey guys, new problem. Soon I will have replaced everything.

Temps are getting a little high. After shutting down, the temp guage always shoots up to around 210, but this seems normal. Temp falls when we are under way again. But now it's running about 210 all the time, sometimes it'll drop to around 200. Thermostat is a 160 degree. I haven't yet checked it for sticking shut, but i'm going to. The impeller is in perfect shape. nothing is in the transmission cooler, i've blown back through it and made sure it was clear.

The other strange thing is after stopping, I can hear water boiling in the starboard exhaust hose, which just so happens to be the side I just patched a hole in the muffler. The muffler still seems to be leaking, but I can't tell from where.

I'm going to check the thermostat (and change to a 140* at the same time) and check all of my hoses to the starboard exhaust manifold. Anything else I should check?

[Workin' 4 Toys]

Originally Posted by H20skeefreek

Hey guys, new problem. Soon I will have replaced everything.

Temps are getting a little high. After shutting down, the temp guage always shoots up to around 210, but this seems normal. Temp falls when we are under way again. But now it's running about 210 all the time, sometimes it'll drop to around 200. Thermostat is a 160 degree. I haven't yet checked it for sticking shut, but i'm going to. The impeller is in perfect shape. nothing is in the transmission cooler, i've blown back through it and made sure it was clear.

The other strange thing is after stopping, I can hear water boiling in the starboard exhaust hose, which just so happens to be the side I just patched a hole in the muffler. The muffler still seems to be leaking, but I can't tell from where.

I'm going to check the thermostat (and change to a 140* at the same time) and check all of my hoses to the starboard exhaust manifold. Anything else I should check?

I am sure I am going out on a limb here, but why did you not replace the mufflers instead of patching. Let's see a photo of your patch job. I doubt it is the thermostat, and you should have the temp you have. I would NOT go to a lower temp stat. It is not going to help do what you are trying to accomplish. All it will do is open sooner, and you don't want that!!

[pup]

check the exhaust manifolds for restriction. over time the manifolds will pack with scale & rust. you should be able to remove the water lines to the manifold & blow through the manifold easily. poor coolant flow through the exhaust will cause an overheat condition . not enough water can also wreck the mufflers.
my boat started running hot last year. i checked the basic stuff first all was ok. 1 manifold was packed with rust. i had to remove it, take it apart & clean it out using a pressure washer. all ok after that.

[H20skeefreek]

I didn't replace the mufflers b/c they are 130 bucks each. I don't have a picture, b/c the patch job is inside of the hose (right at the end of the muffler). The repair isn't mid muffler, but right at the end (transom end). I was taking some water in near there, so i took the hose off of the muffler and found a crack where it looked like the hose had been overtightened. I patched it with epoxy, and the repair seemed solid.

I don't see how it could be the cause of the overheating, but i'm open to suggestions.

I was only planning on changing the stat b/c i've always thought that I shouldn't be getting that hot, are you saying otherwise? I've always been told I shouldn't be going over 180*. I wasn't planning on changing it to fix this issue.

PUP, i'll check the manifolds when I get to the boat next time.

[JimN]

Make sure the water has a clear path from the circulating pump through the exhaust manifold outlets. Also, check the thermostat housing hole and see if a chunk of impeller fin is stuck in it. Make sure the raw water pump is turning in the right direction. I know this sounds odd, but it can be assembled in a way that it turns opposite of what it should.

[6ballsisall]

Originally Posted by JimN

Make sure the water has a clear path from the circulating pump through the exhaust manifold outlets. Also, check the thermostat housing hole and see if a chunk of impeller fin is stuck in it. Make sure the raw water pump is turning in the right direction. I know this sounds odd, but it can be assembled in a way that it turns opposite of what it should.

Hey Jim while we got you on here and we are on the subject. My 95 PS190 with the 275hp motor likes to run around 180 degrees while skiing. That seems a little high provided the gauge is accurate. I haven't pulled the impeller but intend to this weekend as a new one came today from Skidim. I'll check the fresh water lines too. Is this a high temp for this boat with a heater on it?

[H20skeefreek]

Originally Posted by JimN

Make sure the water has a clear path from the circulating pump through the exhaust manifold outlets. Also, check the thermostat housing hole and see if a chunk of impeller fin is stuck in it. Make sure the raw water pump is turning in the right direction. I know this sounds odd, but it can be assembled in a way that it turns opposite of what it should.

That's the next thing i'm doing, checking the water pathways. though, the impeller is perfect, and the waterpump hadn't been taken off all season. I changed the thermostat late last season, so i can't see it sticking, plus, the boiling water on one side only makes me think the problem is on that side only.

this may be a silly question: can a blockage or an air leak for that matter on one side of the exhaust cause the whole motor to heat up?

[pup]

when the thermostat opens, the hot water passes through the tstat & dumps out through the exhaust manifolds. restricted manifolds will reduce the flow of hot water leaving the engine. even though the tstat opens, the water has no place to go. one plugged manifold can cause an overheat condition.

[Bobby]

maybe that's why mine is overheating after new hoses, circulation pump, impeller and thermostat. Now i have something to do tomorrow while the gf is out of town.

[H20skeefreek]

Originally Posted by pup

when the thermostat opens, the hot water passes through the tstat & dumps out through the exhaust manifolds. restricted manifolds will reduce the flow of hot water leaving the engine. even though the tstat opens, the water has no place to go. one plugged manifold can cause an overheat condition.

I guess I meant to say from the muffler, not the whole exhaust system on one side.