Suzuki DF300 "overheat alarm"

[Thumper363]

I am not sure if it has been covered before, but the other day while 40 miles offshore and idling my 2015 DF300 overheat alarm went off and my engine went into safe mode. Within 1 second I looked at the SMIS gauge and the temp was 131, which is clearly not overheated. I also immediatley jumped on the bracket and felt the piss water, and it was cool (131).....so the bottom line is the engine was clearly not overheated, but the alarm went off. Any suggestions or previous experiences with this?

I turned the engine off, and restarted it and ran it another 8 hours that day with zero issues and no high temps.

[Moonlighter]

Possibilities are several.

- faulty temp sensor - Have dealer look at the data from the SDS system;
- Stuck thermostat
- you simply picked up a plastic bag or other obstruction on the leg that was dislodged as soon as you backed off into neutral.
- Water pump impeller is damaged, either from ingesting sand/mud at some stage, or possibly if the engine has been run out of water, or without good water supply to the muffs for even a few seconds. Thus the impeller tips melted, but can still pump emough at speed to keep cool but not at idle speeds.

Pardon me asking, but you dont flush it using the flush port AND run the engine at the same time do you? That will burn the impeller very quickly. Some people dont realise that you cannot flush Suzukis that way.

[Thumper363]

Possibilities are several.

- faulty temp sensor - Have dealer look at the data from the SDS system;
- Stuck thermostat
- you simply picked up a plastic bag or other obstruction on the leg that was dislodged as soon as you backed off into neutral.
- Water pump impeller is damaged, either from ingesting sand/mud at some stage, or possibly if the engine has been run out of water, or without good water supply to the muffs for even a few seconds. Thus the impeller tips melted, but can still pump emough at speed to keep cool but not at idle speeds.

Pardon me asking, but you dont flush it using the flush port AND run the engine at the same time do you? That will burn the impeller very quickly. Some people dont realise that you cannot flush Suzukis that way.

Thanks for the suggestions. No I NEVER flush and run the motor, as I know that will burn it up quickly, and I see people doing it all the time. Only time I run the motor is when I use the muff's and tape over the low water pickups.

I think the point was that the motor was NOT overheated.....no possibility of a bag, etc. I religiously watch the temp gauge and it never was above 131, and within 1 SECOND I looked after the alarm it was 131. So the issue to me has to be a faulty relay or temp sensor?

[castorlee]

Did you ever find the solution to your problem?

[Murray]

If you tap on Thumper363 you’ll see ha hasn’t been on since 2016. Best to start your own post.