Here we go again

[bassyac]

Hello
Here we go again, My DF300 is giving an overheat alarm after idling/trolling for 2 hours. it has 2 gauges and is hooked up to the NMEA network. A buzzer goes off and a huge bubble action goes on. the gauges read overheat, the Garmin 1040XS unit reads Engine warning-overheat, however all the temperature gauges read 138 degrees F. Shut down, Start-up Bring up the rpm's all is fine. Ran for 1 1/2 hours at 3900 rpm's, the engine did not go over 142 degrees.
The telltail never stopped. slow at idle but really goes at higher rpm.
Thank you
John

PS Grant took my post off your now "sticky" post, congrats. Did not think my post was appropriate. More good stuff coming with the Suzuki&the flyboy

[Moonlighter]

Obviously those temps shouldn't be setting off alarms. Were there any signs of overheating from the engine - any steam visible anywhere etc? Nothing to indicate actual overheating?

The mechanics here may be able to offer suggestions, my only thought is a temp sensor might be playing up? Not sure if there are more than one of them on the DF 300's??

John - I was surprised that the Mods were onto the "sticky" request for the networking thread so quickly. Good that it's now up there!!

I am trying to get the interface software uploaded to a file hosting site. If you get a chance would you click on one of the links and see if you can access them, and let me know? Someone said you may have to join the file hosting site to access them - it's free, anyway, but would be good to know.

Some of us have talked about starting a thread showing our fishing exploits from our Suzuki powered boats. Some photos of that young bloke with some big fish on the end of his line would go nicely there!

Cheers

Grant

[Harper]

John, I think the alarms are set off also by an exhaust gas temp sensor. And if this is the case, I would think that a faulty EGT sensor would alarm, even with normal water jacket temps. Might want to check that out.

[bassyac]

Grant I did and you do have to join dropbox, it is easy and free. I took the the little guy into the ocean for the first time, daughter was a nervous wreck, he had his first fish on and threw the rod overboard. I have now tied another rod to cleat.
Mike Going back to the dealer, later today, with your suggestions.
I do not know why the lower throws out so much bubbles when the alarm goes off

Thank you
John

[bassyac]

John, I think the alarms are set off also by an exhaust gas temp sensor. And if this is the case, I would think that a faulty EGT sensor would alarm, even with normal water jacket temps. Might want to check that out.

Mike
Spot on,he said it happened to other DF300 & DF250 both 2014's

[Harper]

Thank you for the feedback, John. That's good to know. Hopefully now your trolling for the big one will suffer no more interruption.

[bassyac]

OK
That was not it(exhaust gas temp sensor) Suzuki rep said. Suzuki rep and dealer were on boat, last week, they got the engine to do the overheat and bubble thing. now both are scratching their heads. It still runs great just do not idle it for a long time. They will get back to me in a day or so. No lost time on the water.
If 1 bank of cylinders is 10 degrees warmer than the other cause it????

[artdf175]

What year is the engine and how many hours?
I can only suggest a water leak / bypass valve problem / engine intermal corrosion allowing cooling water to dump back into exhaust
Bubbles- when the engine overheats it boils the water around the cylindr head
See my photo there were two places water bypassed the head at idle
Photo is the inside of the flush port
The hole dumps water back into the exhaust
There has been problems with the copper water tube that feeds water from the lower unit/water pump to bottom the oil pan gaskets worn out
Art

[bassyac]

Art
Thanks for the response, The engine is a 2014 with approximately 180 hours.
It is under warranty that is why the dealer is on my boat. He would let me know, if they come up with anything. They both think it might be a blockage in the powerhead. Once you boost up the RPMS above 650 everything is back to normal. When it runs at high RPM's no problem at all. Temps run in the 130's
John

[artdf175]

John obviously you don't have so many hours that you would expect corrosion
type problems
You did not mention checking the impeller
Without the book I think the impeller due an inspection
I think it is recommended to be replaced at 200 hours
Art

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[Solarman]

The ”here we go again” makes me feel like this has happened before?

Any chance of a restriction/ interference on water intake side of pump that would only occur at low RPMs? Maybe a slight defect in water pump cup/ housing? You do mention lower pee stream at low RPMs, that does normally happen at idle, but generally as soon as you increase RPMs - trolling, pee stream should increase.
I really can't imagine any kind of salt/ corrosion blockage on such a new motor.

Just saw your other post.

Yes John, I do recollect the fuel problem.
I now understand the ”here we go again”.
Hope there were a few nice fish between the problems.

This might change my prognosis to something like a bypass valve sticking/ hanging open? Maybe allowing (at lower RPMs) too much water to flow through exhaust instead of closing down a little more for powerhead flow?

Good luck. Post us back if they find out anything.