Engine temperature

[jaywoodz]

A few weeks ago, I installed a new hot water heater and had to remove the large pipe that's parallel to it. It was an air pipe that went straight down into a large cylinder that also had 2 other pipes going into it. One was the exhaust out to the side of the boat. Well, long story short.. I didn't notice that we drained all the radiator fluid out. Started the engine and it got hot and threw the beeping sound at the helm. No harm done, we cut if off, filled the radiator up and let it run some and cycle through. It actually overheated again, going over 200 degrees. Left it off, came back the following week and turned it on, now it's 180 or so. What's the ideal temp these should be running? The engine is in my info at the top right of this post. 06-07 models.

 

[Xplicitlnck]

Ok gunna give this a shot but I could be wrong. First assuming your fresh water cooled the water heater should be connected to your water pump to feed the back to the engine. Second. The 2 small pipesinto a large cylinder is you exhaust. You should not have had to touch that unless you needed room to get the heater in and out and that cylinder should not have coolant in it just raw water mixed with your exhaust fumes there for no coolant would drain by removing these pipes. Now as for low coolant. Adding the heater would mean you have to add coolant to fill the lines going to th heater and the heater itself. If you had a heater and simply replaced it you would still have to add fluid to replace the coolant you spilled out when you removed the lines to the old heater.now once you finished your install and put all your lines back on (assuming you marked the hoses and put them back in the proper order, feed line to heater intake and discharge outlet back to the engine) you need to add coolant. After you add coolant you need to burp the system. (Remove all air. By removing the lines you allowed air pockets in and air heats up a lot faster then water.) To do this open bleeder valve and heat exchanger cap WHILE ENGINE IS COLD. And start motor. Leave valve and cap open and let it get up to temp. Keep an eye on the temp to make sure it doesnt get to hot. Let all the air bleed out and fill A S it spills until it runs for a good amount of time without burping.then close valve and install cap. Let it run and make sure temp does not rise above 170 180 or whatever your normal operating temp was. After all that is done just be sure to keep an eye on the over flow res bottle for a couple of trips and add as needed.

If you had coolant in you exhaust cylinder you have much biggr problems. Again I could be wrong but I dont think I am

 

[ardeprint]

You may have an air pocket in your fresh water (coolant) system. Try bleeding out any air in the system. Only coolant should be flowing through.

 

[Xplicitlnck]

I guess that was a much easier explanation then my mumbojumbo. Well put sir

 

[jaywoodz]

Ok gunna give this a shot but I could be wrong. First assuming your fresh water cooled the water heater should be connected to your water pump to feed the back to the engine. Second. The 2 small pipesinto a large cylinder is you exhaust. You should not have had to touch that unless you needed room to get the heater in and out and that cylinder should not have coolant in it just raw water mixed with your exhaust fumes there for no coolant would drain by removing these pipes. Now as for low coolant. Adding the heater would mean you have to add coolant to fill the lines going to th heater and the heater itself. If you had a heater and simply replaced it you would still have to add fluid to replace the coolant you spilled out when you removed the lines to the old heater.now once you finished your install and put all your lines back on (assuming you marked the hoses and put them back in the proper order, feed line to heater intake and discharge outlet back to the engine) you need to add coolant. After you add coolant you need to burp the system. (Remove all air. By removing the lines you allowed air pockets in and air heats up a lot faster then water.) To do this open bleeder valve and heat exchanger cap WHILE ENGINE IS COLD. And start motor. Leave valve and cap open and let it get up to temp. Keep an eye on the temp to make sure it doesnt get to hot. Let all the air bleed out and fill A S it spills until it runs for a good amount of time without burping.then close valve and install cap. Let it run and make sure temp does not rise above 170 180 or whatever your normal operating temp was. After all that is done just be sure to keep an eye on the over flow res bottle for a couple of trips and add as needed.

If you had coolant in you exhaust cylinder you have much biggr problems. Again I could be wrong but I dont think I am

Thanks for the info. But do you know the normal operating temp for these engines? I think that would greatly help. I'm not sure at what temperature the sensor goes off and it's claimed as overheating.

 

[Bob & Sue]

It would depend on what thermostat is in them mine is 160* it runs at just a little under 170* you may want to change the thermostat if you don't know which one you have. If memory is correct sea water cooled is 140* FWC is 160* thermostat. Someone else may have more info I'm not a mechanic.

 

[jaywoodz]

It would depend on what thermostat is in them mine is 160* it runs at just a little under 170* you may want to change the thermostat if you don't know which one you have. If memory is correct sea water cooled is 140* FWC is 160* thermostat. Someone else may have more info I'm not a mechanic.

Yes, mine is not sea water cooled I don't believe. I use coolant 50/50. So, it runs around 180-190. It doesn't quite set the alarm off but it has before.

 

[mainstream]

Yes, mine is not sea water cooled I don't believe. I use coolant 50/50. So, it runs around 180-190. It doesn't quite set the alarm off but it has before.

According to mercury manual MPI with closed cooling is 170 seawater cooled is 160 hope this helps

 

[ardeprint]

anything above 180 for your engine is hot, watch out. Anything over 190 is STOP! At 200 you are boiling water and could damage your engine. Make sure your gauges are accurate. I have a gauge that reads 180-185, but the actual engine temp is 170-175.

 

[Dsybok]

My closed cooled 350 mags run right on the button at 170 and the needle never budges when they are warmed up.

 

[rbryn]

I have a similar problem on my seawater cooled system where the gauge sits at a constant 175. What is the best way to measure the real water temp to see if the gauge is a little off?

Sent from my DROID RAZR using Tapatalk 2

 

[psubill78]

If you have twins- try swapping the senders, or wires to the senders, see if your gauge flips between the 2 sides.

 

[Kon Tiki]

It may becoming time to look at your exhaust manifolds and risers, these engines should be running at no greater than 170. How many hours on the engines since the last replacement, when wascthe last dewater pump replaced.

This is the classic scenario of pay now or play alot more later.

 

[2000SEARAY280SS]

I use an IR thermal thermometer to validate the temp of my engines. They are pretty cheap now and can be used in multiple ways. You can check the temp by just shooting the area you want a temp of. risers thermostat housing exhaust water all of you pipes compare left and right sides you get the picture.

The analog gauges tend to be off from the actual measured temp at the sensor. This is how i calibrate my analog gauge. What the IR temp measures and what the gauge shows is the delta. I generally have to subtract what is read on the housing with what is on the gauge to get the real temp of the engine.

I have compared the IR value with the computer measured value and they are generally within a few tenths of a degrees. I have a Rinda scan tool to read the computer.

I rely on the computer beep to tell me that the engine is really overheating.

You have a temp issue and the IR thermometer will help you isolate the location.:grin:

 

[rbryn]

I've got a single engine, raw water cooled, saltwater use.

it's been 4yrs on the existing manifold/risers and we recently checked the temps on them by hitting them with IR temp gauge Manifolds showed an even heat across them at 163 degrees, temps were within 1 degree across then entire thing... We're hauling this weekend to replace zincs, do the drive oil change and repaint the bottom... thinking it's probably time to swap the manifolds and risers to be safe.