Is 235 too hot?

[luv2fishN.M.]

just installed a new impeller, new water pump, new thermostat and new temp gauge with sending unit. i have a 1988 4.3 mercruiser. the temp holds steady at 235! is this too hot? whats the optimum running temp supposed to be? did i miss something? thanks.

 

[deves3000gt]

Re: Is 235 too hot?

I am not sure what the temp should be but i'm pretty sure 235 is way to hot.

 

[JustJason]

Re: Is 235 too hot?

235 is way to hot... as far as what should it run at. Do you have raw water cooling or fresh water cooling?

 

[windsors03cobra]

Re: Is 235 too hot?

Most engines need to live below 210 to survive, 180-190 is nice.

 

[luv2fishN.M.]

Re: Is 235 too hot?

whats the difference between fresh and raw ? there is not a radiator, if thats the difference. im sorta new to I/O could you please give me an explanation.

 

[mylesm260]

Re: Is 235 too hot?

Raw water: The lake/ocean water cools your engine directly

Fresh water: The lake/ocean water cools your heat exchanger. Then Antifreeze/water circulates between your engine and your heat exchanger.


If your running 235 in a raw water cooled system, your engine would corrode very very quickly.

If your running 235 in a closed cooling system, your still way out of spec, but your not quite as screwed.


First thing you should do is feel your manifolds when the engine is running. Are they cold/warm, or are they piping hot?

Next, pull your thermostat and test it.

Did you wire your sensor and gauge correctly?
Where did you buy your thermostat from?

 

[boat1010]

Re: Is 235 too hot?

Yep 235 is too hot.. Are you sure that the temp Gage is right? If you have don all you said I would surly check that. Does it exhaust through the lower unit or through the hull? is it is through the hull you should be able to feel the water coming out and see if it is really that hot. Have you tried putting "ears" on it and seeing if the pressure in makes it run cooler? Just some thoughts. Good luck..

 

[Don S]

Re: Is 235 too hot?

A raw water cooled engine does not have a heat exchanger (a place for antifreeze) boats do NOT have radiators. Raw water cooled boats generally run in the 160 to 170 degree range, those with a closed cooling system (with heat exchanger and antifreeze system) run at 180? and NEVER more than 190. Matter of fact, in a boat you start worrying when the temp gets to 190? because something is wrong (Unless you have a Volvo 4 cyl rubber band engine, then 190 is normal)
So if you seen 235, then you had a serious overheat and need to find out why.
Get an IR temp gun and verify your engine temp.

 

[windsors03cobra]

Re: Is 235 too hot?

Fresh and raw are the same, sometimes called sea water cooling.
Closed cooling systems use antifreeze coolant for the engine, a sea/raw/fresh water pump cools the engines antifreeze coolant with a heat exchanger.

A typical heat exchanger, think radiator that uses water to cool antifreeze coolant instead of air.

 

[Don S]

Re: Is 235 too hot?

Fresh and raw are the same, sometimes called sea water cooling.

WRONG, They are not the same .
I know you think you know this stuff, but you don't so slow down and stop giveing wrong advise like you know what you are talking about.

 

[luv2fishN.M.]

Re: Is 235 too hot?

in that case its raw system. the manifolds dont feel too hot, but the passenger(right side of the motor looking at it from the front of the boat) is hotter than the left side. i can hold my hand on both of them so there not too hot, i think! yes i did install the sensor correctly. bought a new one with numbers cause i thought the old one was bad. they read the same. dont know what to do?

 

[luv2fishN.M.]

Re: Is 235 too hot?

well hell! now im not sure what kind of system mine is. i'll look for a picture and see if i can post it. the boat is a 1988 regal sebring w/ a 4.3 mercruiser alpha one. the water shoots outa the hull if thats halps out any. thanks

 

[Don S]

Re: Is 235 too hot?

well hell! now im not sure what kind of system mine is.

Well, it's easy to figure out. Do you have a heat exchanger and an antifreeze system? If you do, you have what is called a closed or fresh water cooling system. The fresh water being the antifreeze side.
On a raw water or sea water cooled system. the water from outside the boat is what cools the engine. Even if you are in a fresh water lake. It's still called a raw or sea water cooled system.

the water shoots outa the hull if thats halps out any. thanks

Not sure what that's about, pictures would be a good thing.

 

[luv2fishN.M.]

Re: Is 235 too hot?

my motor looks just like this one. raw or fresh? thanks

http://www.gasseling.us/BoatMotor1.JPG

 

[JustJason]

Re: Is 235 too hot?

Okay so on to your problem.

just installed a new impeller, new water pump, new thermostat and new temp gauge with sending unit. i have a 1988 4.3 mercruiser. the temp holds steady at 235! is this too hot?

Why did you install all of that stuff? Did you do it as part of preventative maintence or were you having a temperature issue to start with? Was it that hot before you installed everything?

In any overheat... you verify the temps first with an IR temp gun. If you verify the overheat you always always always start at the impellar, and work your way foward.
When you installed the impellar did you remember the key? Did you rotate the vertical driveshaft clockwise while you pushed down on the upper water pump housing?
If you don't specifically know the answers to those 2 question then you need to tear back into the waterpump.

 

[Don S]

Re: Is 235 too hot?

It's a raw water cooled system

After that, what Jason said.

 

[JustJason]

Re: Is 235 too hot?

Holy picture batman.... That needs to be resized to 800x600.

Not that the picture matters that much to me. Now that I see it here are a few things that could use some attention after you get your overheat fixed.

1rst. Double clamp that fuel line going into the filter housing.
2. Clean up and paint those pulleys before you start throwing belts.
3. The fuel fill hose looks awefully close to the manifold. Any chance you can relocate it? It also looks fairly old. Any dates stamped on it?

 

[luv2fishN.M.]

Re: Is 235 too hot?

bought the boat a couple weeks ago. took it to the lake and it would over heat at an idle. once the rpms were up too 2500 it would cool back down. looked at the impeller. was bad. the housing was melted to be exact. replaced the water pump because some water was comming outa the weep hole. just figured i would replace the thermostat while i was at it. and yes followed the instructions very close when installing the impeller. sorry about the huge pic! its the only one i could find. thanks.

 

[Don S]

Re: Is 235 too hot?

Did you replace the lower housing of the water pump also? They melt too, and cause air leaks when up on plane. At low speed, they are still under water.

 

[luv2fishN.M.]

Re: Is 235 too hot?

yep! replaced the whole thing. maybe i'll take it apart again and re check everything.