I have a 4 stroke Suzuki that has an overheating alarm going off. You crank it and run it on plane for 20 seconds and the alarm goes off and the rpm’s cut back. When it first started doing this, it was intermittent and random. Now it does it any time you’re on plane even at the start of the day and when it’s 30 degrees outside, so the motor isn’t actually overheating, as it is cool to the touch. To get the alarm to shut up, all you have to do is turn off the key. Crank it back up and the alarm stays off till you get back on plane. Water pump seems to be fine as it is peeing. Could it be the thermostat? Could it just be a sensor that’s malfunctioning? Need some help.
Sounds like the sensor going bad. If the pee stream is not too hot then it is not really overheating. You should also be able to touch the engine and not get burned if the water is that cool. Take out the thermostat and run it to see if that helps. Can you replace the sensor or is it cast into the block.
Not sure where the sensor is. I’ll start with the T-stat and go from there. How hard is it to find, test, replace the sensor?
When is the last time you changed the oil/reset your service alarm? Turned out mine did that and it was the alarm for service.
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the service alarm will not reduce power
are you sure its overheat and not low oil pressure?
i have a 175 suzuki 4 stroke and it was doing the exact same thing it beeped and cut rpms back and it turned out my oil was low…might wanna check on that!
211 key west 175 suzuki
Thanks for the suggestions guys. It is definitely the temp light that comes on. We don’t run the boat very much. Mostly a little during the summer and fall for inshore fishing. With that said, the last time I checked the oil, it was fine. Also, the boat hasn’t been serviced in a couple of years. Since I don’t use the boat extensively, I haven’t dove into the problem head on. Just figured I’d come to the experts on Charleston Fishing first to get some ideas. Thanks again.
just because the water coming out of the pee tube is cool doesnt, doesnt mean the engine is.
that simply means you have water pressure up to that point
what year and hp is the motor?
The motor is a 40 hp. Not sure on the year model. I think it is a 2001 or 2003. I really don’t believe that the motor is actually overheating. The alarm will go off first thing in the morning when the air temp is 30 degrees. The engine itself will even be cool. Could it be something else causing the alarm/rpm cutback such as low pressure from water pump, t-stat, sensor, time to change the oil, etc.? The water pump has never peed super hard. More of a steady stream with decent pressure, but really seems to be fine.
it takes less than a minute for the motor to reach temp under load, regardless of air temp.
a faulty sensor could definately cause your issue, but you need to take the engines temp at the sensor location before you condem the sensor. with a suzuki of that age, you could easily have a corrosion issue or blockage, creating a hotspot.
Don’t know about 4 strokes, but there was a built in false alarm in older 2 strokes. The temp alarm didn’t really measure temp, it was keyed by lack of water flow. There was a pendulum arm in a water jacket that would keep a switch closed (and alarm off) if water was flowing. Problem was, sand/crud could cause the switch to not close completely and issue an alarm even with normal water flow.
With all that said, looks like yours has an actual sensor thermocouple, but I’d start the search there. ~ $60 from Brown’s Point … 