what does the overheat alarm sound like

Sounds to me that you really, really need to get a manual and understand what causes alarms on your boat.

In a single engined boat. . you don't want to be trying this out while on the water.

In my boat (pre smart craft) the dash oil guage and dash oil temp indicator originate from *different* sensors than ones that sound the alarm. I would be surprised if it is different on your boat. It is very important that ALL the sensors work properly. After all. . if you hear an alarm, and your engine temp gauge reads hot. . now that is TWO THINGS telling you that you have a problem. . .

If your dash temp gauge is bust. . then when the alarm sounds you will be guessing at what the problem is. . . while the engine is self destructing.

On my engines, the hottest component is the oil filter. Reads much higher than the thermostat settings. The thermostat housings should be close to the setting and close to what you see on the dash (afterall. . the sensors are in this area). The risers and elbows should be substantially cooler. My thermostat is a 165, and the risers/elbows are all in the 125-140 range. The important thing is that both sides read the SAME. If one is substantially hotter, that means flow is restricted on that side (which is a bad thing)
 
Hey comsnark--I was at the sea ray dealer and the service department told me it is normal for one elbow to be hotter then the other. He said the reason is because the water gets to one side quicker then the other side. He said one side could feel warm and then the other side feel hot. I have noticed this on my engine. one time the left elbow was hotter and the other time i checked the right elbow was hotter. So that seems to coincide with what the service tech told me.

thanks
art
 
greenstreak said:
I have a 2000 sundancer 270 with mercruiser 7.4 mpi with bravo III. I was told the overheat alarm would be a solid sound from a sea ray dealer. I had an alarm go off today while on cruise and it was a loud beep. It would beep, maybe 1 or 2 second pause and beep again. I came off cruise and idle for a couple of minutes and the beep went away. Not a solid sound. Any ideals?

Thanks

art
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The answer to your question, "What does the overheat alarm sound like?" is roughly similar to the sound that a credit card machine makes just after processing your charge.:smt021
 
greenstreak said:
Hey comsnark--I was at the sea ray dealer and the service department told me it is normal for one elbow to be hotter then the other. He said the reason is because the water gets to one side quicker then the other side. He said one side could feel warm and then the other side feel hot. I have noticed this on my engine. one time the left elbow was hotter and the other time i checked the right elbow was hotter. So that seems to coincide with what the service tech told me.
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I know people do it, but I am not sure I would want to quantify how hot risers are with my hand. On my engines, the risers were 125-140F with everything normal. If things are not normal. . they are going to be closer to 200F. That is too hot for me to mess with.

I don't know what you mean when one side is warm while the other is hot. Is that a 125-140 difference, or a 90F-200F difference? For the former, I wouldn't sweat it. For the later. . I would start wondering about restrictor gaskets.
 
comsnark--I meant between the 2 elbows there are about 25 degrees difference. My right elbow is around 120 and the left elbow about 145.

art
 
Slight differences are normal from side to side, I just did an exhaust manifold job for a pair of 6.2's and the water supply elbow and manifold boss had four pieces of old impeller stuck in them .This made the port side very hot to the touch compared to the starboard side.I have found this spot easily blocked with debris,and causes wild swings in elbow temps.
 
According to my mechanic, a 25 F delta between sides would be fine. I honestly would not start to sweat until one of the sides got to the 190F range. The key thing, I imagine, is not to have boiling water in the risers. That would really screw up both flow and heat transfer.

Yeah. . the water will boil at slightly over 212 F. .. but I don't know how accurate these type of measurements are.
 
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The service department at sea ray said the port side of engine will always run cooler if everything is normal on a mercruiser. Each time I have checked my engine that is the coolest side on mine. I changed out both the heat sensor and the thermostat, so now I will see what the gauge shows when I take it out again.

art
 
greenstreak said:
The service department at sea ray said the port side of engine will always run cooler if everything is normal on a mercruiser. Each time I have checked my engine that is the coolest side on mine. I changed out both the heat sensor and the thermostat, so now I will see what the gauge shows when I take it out again. art
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Keep us posted on the alarm - I am curious. BTW - I read your post on boat us on the manifold issues you had with your old mechanic - All I can say is wow- you must have the patience of a Saint!
 
If you are having issues, I would recommend getting an IR gun. I bought a cheap one from Sears for about $80 when I was having problems. The other thing that can be done on my engines (don't know about yours) is that you can switch the sensors between the gauge and the alarm. That can help you troubleshoot bad instrumentation.

Port side runs colder eh? I will have to check that out next season!
 
hey comsnark---You mean the manifold problem on my Chaparral 260 when the stupid mechanic/owner did the inspection and said everything was ok and then I got water instrusion after they put manifolds back on. That was a nightmare.

I went out this weekend and I had no alarms and the boat ran fine. I believe the alarm was from the outdrive reservoir being a little low. I think I have a small leak getting into the bellow and running into the bilge. If so I will have to have the drive pulled and gaskets installed.

Yes the port engine will run cooler. that is what Parker boats said. I got an ir gun and when I check the temp the port side is cooler on the manifold and riser.

Thanks
art
 
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The answer to your question is a loud high pitch tone. This will sound continually until you shut down the engine and it cools down.
 
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